A lot has changed since last season. Some has stayed the same. Here's a brief overview of all of it.
RB: Andre Ellington played hurt in 2014 and his production suffered. He should start the season healthy in 2015. Third-round pick David Johnson should be the number two back, but he won't eat significantly into Ellington's workload. Stepfan Taylor, Kerwynn Williams, and Marion Grice will battle for roster spots.
WR: Michael Floyd had way too many drops last season, but remains a field-stretching deep threat. Larry Fitzgerald looked slow last season -- perhaps because of minor knee injuries, or perhaps because he was sometimes lost in the new offense. It is questionable whether he'll bounce back in 2015. John Brown was the team's best playmaker last season, but will probably remain behind Floyd and Fitzgerald for another season. Jaron Brown should be WR4.
TE: Troy Niklas was hampered by injuries as a rookie. He will likely start in 2015, but the tight ends in Bruce Arians' offense are mostly blockers. Backup Darren Fells might compete for playing time as a blocker. Gerald Christian has the most upside receiving potential of the group, but that's not saying much. John Carlson and Rob Housler are gone.
RB: Third-round pick Tevin Coleman will be 1A on the depth chart with Devonta Freeman 1B. Antone Smith will be the change-of-pace guy like last year. Patrick DiMarco is the fullback. Steven Jackson and Jacquizz Rodgers are gone.
RB: Justin Forsett returns as the starter. Rookie Javorius Allen will compete with Lorenzo Taliaferro and Fitzgerald Toussaint for backup duty. Kyle Juszczyk is replaceable at fullback, but not yet replaced. Bernard Pierce is gone.
WR: Steve Smith should keep the same role as last year, while rookie Breshad Perriman replaces Torrey Smith. After that, Kamar Aiken, Marlon Brown, and Mike Campanaro are all in the running for spots in the rotation. Rookie Darren Waller is a project, but his size-speed combo makes him a versatile receiver who could get snaps at TE as well as WR. Torrey Smith and Jacoby Jones are gone.
TE: Dennis Pitta is coming off of hip dislocations in consecutive years, and his status for 2015 is uncertain. That means that Maxx Williams and Crockett Gillmore could battle for the starting job, with both playing a role (Williams as the better receiver and Gillmore as the better blocker). Nick Boyle could also make the roster if Pitta can't return, but he's unlikely to make a fantasy impact. Owen Daniels is gone.
RB: LeSean McCoy will be the featured back. Fred Jackson may get some work on passing downs, and maybe at the goal line; but first he has to make the final roster, which is not a foregone conclusion. Anthony Dixon, Bryce Brown, and rookie Karlos Williams will compete for the remaining roster spots. Jerome Felton takes over at fullback. C.J. Spiller is gone.
WR: Sammy Watkins should be healthy (hip). Percy Harvin will start outside, then move to slot in 3-WR sets. Robert Woods is WR3, which is a reduced role for him. Marquise Goodman will compete for WR4, and should have the edge over rookie Dezmin Lewis and UDFA Andre Davis.
RB: Jonathan Stewart will start, but will be limited to 15 touches per game. Jordan Todman should open the season as RB2. Rookie Cameron Artis-Payne will compete with Fozzy Whittaker at RB3. Mike Tolbert is the fullback. DeAngelo Williams is gone.
WR: Kelvin Benjamin and Jerricho Cotchery return as starters. Rookie Devin Funchess is the favorite to win the WR3 role. Jarrett Boykin and Ted Ginn Jr will compete for WR4. Stephen Hill will compete with Philly Brown, Brenton Bersin and Mike Brown to make the final roster.
WR: Alshon Jeffery will play the Demaryius Thomas role in Adam Gase's offense. Rookie Kevin White will replace Brandon Marshall. Edie Royal will be WR3, with Marquess Wilson WR4. Brandon Marshall is gone.
RB: Jeremy Hill returns as the lead back and should get 15-20 touches a game. Gio Bernard should get 8-11 touches in a situation role. Rex Burkhead could see a bit more action this season. Cedric Peerman is mainly a special-teamer. James Wilder Jr and Terrell Watson are likely non-factors. Ryan Hewitt is a stud at fullback.
WR: A.J. Green is a stud. Marvin Jones Jr is healthy (foot) and should start opposite Green. Mohamed Sanu is WR3. Denarius Moore could be WR4. Brandon Tate is mainly a return specialist. Rookie Mario Alford could catch on.
RB: Isaiah Crowell is the favorite to start. Rookie Duke Johnson Jr will compete with Terrance West for the primary backup role, but might be more of a change-of-pace and passing-down back. Shaun Draughn will compete for a roster spot as a passing-down back.
WR: Dwayne Bowe is projected to be WR1. Brian Hartline is projected to be WR2, with Andrew Hawkins in the slot. Taylor Gabriel is WR4. Rookie Vince Mayle could catch on. Marlon Moore is back as a return man. Josh Gordon is suspended for the season.
K: Garrett Hartley was released. Travis Coons and Carey Spear will compete to replace him.
RB: RBBC. Joseph Randle was effective as a change-of-pace runner last year, but may not be suited for a heavy workload. Darren McFadden has shown flashes, but has had trouble staying healthy. He should look better behind the Cowboys' OL than he did behind the Raiders' OL. Lance Dunbar will compete for passing-down snaps. Ryan Williams is a talented, natural runner, but remains unproven and could be the odd man out. Jed Collins should hold off Ray Agnew as the starting fullback. DeMarco Murray is gone.
WR: No change with Demaryius Thomas. Emmanuel Sanders is still WR2, but could move inside to the slot in three-WR sets with Cody Latimer outside. Latimer will be WR3 in what is generally a 2-TE offense, but will get playing time if he shows a better grasp of the playbook. Jordan Taylor has excellent size, and could be a sleeper. Wes Welker is gone.
TE: Owen Daniels will try to replace Julius Thomas, but had a down year in 2014. Virgil Green is predominantly a blocker, but could see more targets with Julius Thomas gone. James Casey will get limited snaps as an H-back/fullback hybrid, and will be used more as a lead blocker than a receiver. Rookie Jeff Heuerman is a fantastic blocker, and an athletic receiver, but is lost for the year with a knee injury.Julius Thomas is gone.
RB: Joique Bell will be challenged by rookie Ameer Abdullah for the RB1 job. Behind those two, Theo Riddick may see little playing time as a third-down specialist. Zach Zenner could make the team as an inside runner. Rookie Mike Burton should be the fullback (maybe more like an H-back). Reggie Bush is gone.
WR: Calvin Johnson returns healthy. Golden Tate will see fewer targets as a result. Corey Fuller could be a deep threat at WR3. T.J. Jones is in the mix. Ryan Broyles is buried on the depth chart. Lance Moore will battle Greg Salas for a roster spot. Jeremy Ross is a special-teamer.
TE: Eric Ebron could double his targets as Brandon Pettigrew's receiving role continues to be way below his 2010-2012 level. Joseph Fauria is a redzone target, but has no real fantasy value as the team's TE3.
Green Bay Packers
RB: No big changes. Eddie Lacy is the lead back, but on a snap count, with James Starks getting some regular work. UDFA Malcolm Agnew could make the team as a third-down type back. UDFA John Crockett is a potential practice squad guy. Aaron Ripkowski may be John Kuhn's eventual successor at fullback, but not this year.
WR: Jordy Nelson and Randall Cobb are the top two WRs. Davante Adams is WR3. Jeff Janis is WR4 in pencil, not pen. Jared Abbrederis will try to hold off rookie Ty Montgomery, who could be a slot receiver with run-after-the-catch ability.
RB: Arian Foster should get 20+ touches a game when healthy. Alfred Blue is the handcuff. Jonathan Grimes is the favorite for RB3. Chris Polk will probably make the final roster. Rookie Kenny Hilliard is probably a non-factor.
WR: DeAndre Hopkins is WR1. Cecil Shorts should start opposite Hopkins, but move into the slot in 3-WR sets, with Jaelen Strong playing on the outside (though Strong could surpass Shorts). Nate Washington looks like WR4, and Damaris Johnson WR5. Rookie Keith Mumphery is probably limited to special teams (and could ultimately move to RB).
WR: T.Y. Hilton returns as WR1. Andre Johnson will start opposite Hilton. Rookie Phillip Dorsett will compete with Donte Moncrief in the slot. Duron Carter (formerly CFL) will battle for a roster spot. Vincent Brown is unlikely to make the team. Reggie Wayne and Hakeem Nicks are gone.
RB: Second-round pick T.J. Yeldon could be a workhorse as a rookie. Denard Robinson is likely relegated to a change-of-pace role. Toby Gerhart should move to H-back. UDFA Corey Grant could make the team as a receiving-down back. Storm Johnson and Bernard Pierce may be odd men out.
WR: Allen Robinson and Marqise Lee should start, with Allen Hurns battling rookie Rashad Greene Sr for the slot position. Rookie Neal Sterling has size, but lacks speed. Ace Sanders may be the odd man out. Bryan Walters is just a return specialist. Arrelious Benn is probably just a camp body. Justin Blackmon is still indefinitely suspended; it's not clear whether he'll be reinstated this year.
TE: Julius Thomas will start. (Bortles is a big downgrade from Manning.) Marcedes Lewis is probably safe as TE2, and will be used mostly as a blocker. Rookie Ben Koyack could make the team as another blocking TE.
Kansas City Chiefs
WR: Jeremy Maclin is instantly WR1. Albert Wilson will battle rookie Chris Conley for WR2. Conley is an athletic freak, but may not fit well with Alex Smith's small-ball mentality. Jason Avant is likely WR4. DaRick Rogers has potential, but is a knucklehead. Junior Hemingway is likely a non-factor. Rookie DaRon Brown is an underdog to make final roster. Dwayne Bowe is gone.
TE: Travis Kelce played only two-thirds of the snaps last season; expect at least four-fifths this year. Rookie James O'Shaughnessy will battle Demetrius Harris for the primary backup position. Blocking TE Richard Gordon is probably the odd man out. Anthony Fasano is gone.
RB: Lamar Miller returns as the starter, but could lose snaps to rookie Jay Ajayi. Ajayi should have the edge over Damien Williams and Mike Gillislee as RB2. LaMichael James is just a special-teamer. Knowshon Moreno and Daniel Thomas are gone.
WR: Kenny Stills will start on the outside. Rookie DeVante Parker should have an edge over Greg Jennings for the other outside spot, but the two will likely rotate. Jarvis Landry should occupy the slot. Rishard Matthews will compete with LaRon Byrd for the WR5 spot. Mike Wallace, Brian Hartline, and Brandon Gibson are gone.
WR: Mike Wallace and Charles Johnson will start outside. Jarius Wright will occupy the slot and should get more targets than last year. Cordarrelle Patterson's role is uncertain. Rookie Stefon Diggs is suited for the slot, but may be a year away from contributing. UDFA DaVaris Daniels is a deep sleeper with upside.
TE: No major changes. Kyle Rudolph, Rhett Ellison, and Chase Ford return. Rookie MyCole Pruitt is a terrific athlete who may be a year away from contributing. Brandon Bostick is probably the odd man out.
New England Patriots
RB: LeGarrette Blount is RB1, but faces a one-game suspension. James White could fill Shane Vereen's role as the pass-receiving RB, but will compete with Dion Lewis and Travaris Cadet for that honor. Tyler Gaffney could find a role. Jonas Gray is an underdog to make the final roster. James Develin is the fullback. Stevan Ridley and Shane Vereen are gone.
WR: Julian Edelman and Brandon LaFell return as starters. Danny Amendola emerged late in 2014 and may keep his momentum heading into 2015. Aaron Dobson will compete for WR4. Brian Tyms could take a step forward and compete for regular playing time. Brandon Gibson and Josh Boyce will battle for a roster spot.
TE: Rob Gronkowski is still a stud. Timothy Wright's role was up and down in 2014, could be more consistent in 2015. Scott Chandler has a role as TE3. Rookie A.J. Derby is a terrific athlete who could catch on but likely won't contribute right away.
New Orleans Saints
RB: Mark Ingram II may get around 240 touches as the lead back, while C.J. Spiller could get around 150 touches as a passing-down back. Khiry Robinson is a talented backup, and could get around 90 touches. Rookie Marcus Murphy is probably just a special teamer. Tim Hightower is probably a non-factor.
WR: Branden Cooks is WR1. Marques Colston is WR2. Nick Toon and Joe Morgan look like WR3 and WR4, but keep an eye on sleepers Brandon Coleman and Seantavius Jones, both of whom are athletic specimens.
New York Giants
WR: Odell Beckham Jr Jr is a stud. Rueben Randle figures to be WR2 unless and until Victor Cruz shows that he's fully healthy. Cruz is rehabbing a patellar tendon and may begin the season on the PUP list. Dwayne Harris may make the final 53-man roster but not be much of a factor on Sundays. Rookie Geremy Davis will play mainly special teams as a rookie. Marcus Harris is a sleeper with some upside; he and Corey Washington will battle for roster spots.
New York Jets
RB: Expect Chris Ivory and Stevan Ridley to split carries if both are healthy. Ridley is recovering from ACL surgery, however, and could start the year on the PUP list. Zac Stacy adds depth in case Ridley is unavailable. Bilal Powell will make the roster for his special teams play. Daryl Richardson looks like the odd man out. Chris Johnson is gone.
WR: Brandon Marshall becomes WR1, and Eric Decker slides to WR2. Rookie Devin Smith is a deep threat who could beat out Jeremy Kerley for the WR3 role. DeVier Posey will battle for a roster spot, but isn't a fantasy consideration.
TE: Jace Amaro dropped too many balls last year, but he returns as the clear starter and could progress in Chan Gailey's spread offense. Jeff Cumberland, primarily a receiver, and Kellen Davis, primarily a blocker, will share backup duties.
RB: Latavius Murray should have the edge over Trent Richardson in the battle for the starting job. Roy Helu could be the third-down back, similar to Darren Sproles in Philadelphia. UDFA Gus Johnson could catch on as a backup. Marcel Reece will be fullback, but was under-used last season (again). Maurice Jones-Drew and Darren McFadden are gone.
WR: Amari Cooper should instantly be WR1. Michael Crabtree should start opposite Cooper, but he could give way to Rod Streater, Andre Holmes, or Brice Butler. All of them could rotate. UDFA Josh Harper is a sleeper with upside potential. Rookie Andre Debose is more likely to see time as a return specialist than as a WR. James Jones is (a bit surprisingly) gone.
RB: DeMarco Murray is an excellent fit for Chip Kelly's offense if he can stay healthy. Ryan Mathews is a strong inside runner who has been fragile. Darren Sproles is still an effective RB, but he's strictly a change-of-pace back behind Murray and Mathews. LeSean McCoy is gone.
WR: First-round pick Nelson Agholor should start immediately opposite Jordan Matthews. Josh Huff and Riley Cooper look like WR3 and WR4, in one order or another, leaving Miles Austin struggling to find a place in the rotation. UDFA Devante Davis is a sleeper who could catch on. Seyi Ajirotutu is strictly a special teamer. Jeremy Maclin is gone.
TE: Zach Ertz appears to be a talent on the rise. Brent Celek was the better run-blocker last season, which limited Ertz' playing time, but Ertz has worked extensively on his blocking technique this offseason, and could get more snaps this year. James Casey is gone.
RB: Le'Veon Bell injured his knee in week 17 last season, but he should be fully healthy entering training camp. He will serve a three-game suspension, however (unless it is reduced on appeal). DeAngelo Williams will start in Bell's place during the suspension, but will fade into the background afterwards. Dri Archer could get a few touches per game. Will Johnson is the fullback.
WR: Antonio Brown is really good. Martavis Bryant is a talent on the rise with fantasy upside due to his proficiency in the red zone. Rookie Sammie Coates Jr will battle Markus Wheaton for the WR3 position. Darrius Heyward-Bey looks like WR5.
TE: Heath Miller is starting to decline. Matt Spaeth is strictly a blocker with no fantasy value. Rookie Jesse James is a project who could be Miller's eventual successor. Michael Egnew is also a project, but the Steelers may have no room to carry him.
San Diego Chargers
RB: Rookie Melvin Gordon III is the instant starter and early-down back. Danny Woodhead will get a lot of the work on passing downs. Branden Oliver is relegated to changing the pace. Donald Brown is a candidate for release. David Johnson is the fullback (and H-back). Ryan Mathews is gone.
WR: Keenan Allen is the team's best receiver; he could line up in the slot more often, helping him get a clean release. Steve Johnson and Malcom Floyd will be WR2 and WR3, in some order or another. Dontrelle Inman and Austin Pettis will battle for WR4 and WR5. Jacoby Jones is mainly a return man. Eddie Royal is gone.
WR: Doug Baldwin returns as the team's best overall WR. Jermaine Kearse returns as the deep threat across from Baldwin. Rookie Tyler Lockett could fit into the slot. Chris Matthews had a breakout game in the Super Bowl and is a great late-round sleeper. Paul Richardson Jr injured his knee in January and could begin the 2015 season on the PUP list. Ricardo Lockette returns but is no lock to make the roster. Ditto Kevin Norwood.
San Francisco 49ers
RB: Carlos Hyde will get the early-down work and Reggie Bush will play on passing downs. Rookie Mike Davis is RB3. Kendall Hunter could occasionally change the pace. Bruce Miller is the fullback. Frank Gore is gone.
WR: Anquan Boldin returns as the possession receiver, and Torrey Smith reunites with him as the deep threat. Quinton Patton and Bruce Ellington will compete for WR3 duties. Jerome Simpson will compete for a roster spot. Rookie DeAndre Smelter is recovering from an ACL injury and is likely a year away from contributing. Michael Crabtree, Steve Johnson, and Brandon Lloyd are gone.
TE: Vernon Davis returns as TE1. Derek Carrier will compete with rookie Blake Bell to be the primary backup. Rookie Rory Anderson has big-play ability but inconsistent hands, and will compete with Vance McDonald for the final roster spot, assuming the team keeps four TEs (not including Kyle Nelson, who is just a deep snapper). Garrett Celek is gone.
St. Louis Rams
RB: Todd Gurley is instantly the team's RB1 as soon as he's cleared to play, but an ACL injury late last season could cause him to begin the year on the PUP list. Tre Mason would start in Gurley's place for as long as Gurley is out, but after that would be relegated to scraps along with Benny Cunningham. UDFA Malcom Brown could catch on as a third-down back. Isaiah Pead, coming off of ACL surgery, may have trouble making the final roster. Chase Reynolds is strictly a special-teamer. Cory Harkey is the fullback (and H-back). Zac Stacy is gone.
WR: Kenny Britt is the Rams' most talented receiver, and can be weakly penciled in as WR1. Brian Quick is coming off of major shoulder surgery, but could be ready for the start of training camp, and is the favorite to start opposite Britt. Stedman Bailey and Tavon Austin will most likely compete for WR3 in the slot, where rookie Bud Sasser could also figure into the mix. Chris Givens and Damian Williams will battle to make the final roster.
Tampa Bay Buccaneers
RB: Doug Martin, Charles Sims, Bobby Rainey, and Mike James are a deep if unspectacular group, and will probably get touches in that order (though Sims could supplant Martin). Jorvorskie Lane will battle rookie Joey Iosefa for the fullback job.
QB: The plan is for Marcus Mariota to start from day one, though some scouts feel that he's not ready to run an NFL offense. Zach Mettenberger will be the backup, but could get playing time if Mariota struggles.
RB: Bishop Sankey returns as the starter, but he'll face a challenge from rookie David Cobb. Expect Antonio Andrews to win his battle with Shonn Greene for a roster spot. Dexter McCluster has a limited role even when healthy, and is coming off a late-season knee injury. Rookies Jalston Fowler and Connor Neighbors will compete at fullback.
WR: Justin Hunter and Kendall Wright return, but Hunter could lose his starting job to rookie Dorial Green-Beckham. Harry Douglas should be the slot receiver. Hakeem Nicks is no lock to make the final roster; he could be overtaken by talented rookie Tre McBride.
TE: Delanie Walker returns as TE1. Anthony Fasano is mostly a blocker at this stage. Craig Stevens is coming back from a torn quad, but is a terrific blocker when healthy. Taylor Thompson is a versatile athlete who may be used mostly on special teams.
QB: Robert Griffin III III is QB1, but may have a shorter leash than generally perceived. Kirk Cousins and Colt McCoy will battle for QB2. (Give Cousins the edge, but note that McCoy played ahead of him at the end of 2014.) Connor Halliday is a camp arm.
RB: Alfred Morris returns as RB1. Rookie Matt Jones may have the edge over Silas Redd for work on passing downs. UDFA Trey Williams will challenge Chris Thompson for a roster spot. Michael Hill is likely a non-factor. Darrel Young is the fullback. Roy Helu is gone.
WR: DeSean Jackson and Pierre Garcon return in their same roles from last season. In the slot, Andre Roberts will seek to hold off a challenge from rookie Jamison Crowder. Rookie Evan Spencer probably won't be a factor as a rookie. Ryan Grant is on the roster bubble.