Here’s a player-by-player look at the Buffalo Bills ' 53-man roster:
EJ Manuel: Being a No. 2 quarterback isn't ideal for the 2013 first-round pick, but it's still a better outcome than where Manuel appeared to be headed when he began training camp poorly.
RUNNING BACK (4)
Karlos Williams: Expect the fifth-round rookie to get a healthy amount of carries behind McCoy after an impressive training camp.
Boobie Dixon: Perhaps the most lively player in the locker room, Dixon is an ideal No. 3 running back and special teams contributor.
Bryce Brown: NFL Network reported Saturday the Bills have had trade discussions involving Brown, whose spot on the 53-man roster likely was saved by Jackson's release.
Jerome Felton: The Bills could use a fullback more than any other team this season, and they have one of the best.
WIDE RECEIVER (7)
Sammy Watkins: With a running game headed by McCoy and Taylor expected to carry the offense, Watkins' production still might not square with his talent level and draft spot.
Percy Harvin: His hip ailment will be an issue if pain returns, but if he can stay healthy, he should contribute to the offense as both a receiver and runner.
Chris Hogan: Still the Bills' fourth receiver, Hogan didn't have a strong training camp but continues to provide value as a depth option and special teams contributor.
Marcus Easley: He won't contribute on offense but should lead the way on special teams for a third consecutive season.
Marquise Goodwin: It's tough to see where Goodwin will contribute this season, and he'll have to wait until his broken ribs heal before doing anything.
TIGHT END (5)
Charles Clay: His right knee gave him problems in Miami all of last season and cropped up again late in training camp, so health could be a concern for an important piece of the Bills' offense.
MarQueis Gray: He'll never be a star, but Gray is an adept pass-catcher and can fill a variety of roles on offense, including as a fullback in some situations.
Matthew Mulligan: A pure power-blocker, Mulligan will get plenty of playing time in Greg Roman's run-heavy offense.
Chris Gragg: His roster spot appeared to be in jeopardy, but the Bills wanted to carry a few extra tight ends, and Gragg earned his spot by picking up his play late in the preseason.
Nick O'Leary: The sixth-round rookie never emerged in training camp or the preseason but could get essentially a redshirt year; don't expect him to dress on game days unless there are injuries ahead of him.
OFFENSIVE LINE (8)
Cordy Glenn: Left tackle enters a contract year and will need to prove he's worth a big new deal.
Richie Incognito: It has been smooth sailing so far in Incognito's return to the NFL.
Eric Wood: He's the glue that must hold together the offensive line and a key leader on offense after the departure of Jackson.
John Miller: The Bills threw the third-round rookie into the fire since Day 1, and he hasn't disappointed; he's the opening-day starter at right guard.
Seantrel Henderson: It has been a boomerang year for Henderson, who ended last season as the starter at right tackle, lost that job to Cyrus Kouandjio in the offseason and won it back in the preseason.
Cyrus Kouandjio: Second-year tackle looked to make progress in the spring, but that never materialized in the preseason; he'll be the swing tackle but is still a question mark.
Kraig Urbik: Veteran took a pay cut to stick with the Bills in the offseason and will serve as the top interior backup along the offensive line.
Gabe Ikard: The Bills essentially swapped former Jets center Dalton Freeman, whom they claimed last week, for Ikard, whom they claimed Sunday.
DEFENSIVE TACKLE (3)
Corbin Bryant: Slightly undersized, he'll fill in for Dareus for the season opener after a strong preseason.
Stefan Charles: A bigger body, Charles could split time with Bryant once Dareus returns from his suspension.
DEFENSIVE END (3)
Mario Williams: After having more of an edge role in Jim Schwartz's "wide-9" defense, expect Williams to play closer to the center of the line in Rex Ryan's defense, although he'll be moved around.
Jerry Hughes: He'll be one of the Bills' more important players as an edge rusher especially since they don't have depth behind him.
Alex Carrington: A versatile backup lineman, Carrington is more of a run-stopper than an edge rusher, so the Bills still could use depth at that spot.
STRONG-SIDE LINEBACKER (2)
Manny Lawson: He'll be important in run support, pass coverage and pass rushing in one of the key positions on Rex Ryan's defense.
Randell Johnson: He's a better fit in Ryan's defense than Schwartz's and should play a role on special teams.
MIDDLE/WEAK-SIDE LINEBACKER (4)
Nigel Bradham: He enters a contract season and couldn't be in a better situation playing behind one of the NFL's best defensive lines.
Preston Brown: Second-year linebacker will need to anchor the Bills' defense and stay healthy; the team doesn't have much depth behind him.
Tony Steward: He injured his knee in the third preseason game and is unlikely to play in the season opener but will be an injury away from starting when he returns.
A.J. Tarpley: Undrafted rookie earned a spot on the 53-man roster after a strong preseason and an injury to top backup Ty Powell.
Stephon Gilmore: Was nicked up late in the preseason but should be ready for the season opener; the Bills will need to lock down the secondary against Andrew Luck and Tom Brady in the first two games.
Ronald Darby: Rookie has been thrust into a starting role and looks to be the weak spot of the Bills' defense for now but offers long-term potential.
Nickell Robey: He should fit well in Ryan's defense as one of the NFL's better nickel cornerbacks.
Ron Brooks: As the fourth cornerback, Brooks would be a liability as a starter but offers value on special teams.
Mario Butler: One of the feel-good stories on the roster, Butler entered the NFL in 2011 and spent three seasons on NFL practice squads as well as last season on injured reserve. He has appeared in just one career NFL game.
Aaron Williams: He'll need to step up as a leader following the loss of his mentor, Jackson, and will need to continue to improve his tackling this season.
Corey Graham: Making the transition from cornerback, the veteran hasn't looked out of place patrolling the deep part of the field.
Duke Williams: He slipped a bit in training camp after looking to be in line for a bigger role, but he still offers depth and special teams value.
Bacarri Rambo: The Bills kept Rambo over Jonathan Meeks; like Williams, he'll have to make his mark on special teams.
Dan Carpenter: Ryan put his kicker on notice after a shaky preseason, but there hasn't been any indication the Bills are serious about replacing him -- yet.
Colton Schmidt: After replacing longtime punter Brian Moorman shortly before the start of last season, Schmidt will enter his second year with the Bills.
Garrison Sanborn: One of the best long snappers in the game.
Jordan Gay: The Bills didn't want to keep a kickoff specialist if they didn't need to, but they feel Gay is one of the NFL's best at kickoffs and a significantly better option than Carpenter.
Marcell Dareus: He'll sit out the first game of the season following two arrests in the 2014 offseason.