Backup QB Thad Lewis to start for Bills at PatsBuffalo Bills quarterback Thad Lewis (9) passes against the Miami Dolphins during the first half of an NFL football game on Sunday, Dec. 22, 2013, in Orchard Park, N.Y. (AP Photo/Bill Wippert)
ORCHARD PARK, N.Y. (AP) -- Bills rookie quarterback EJ Manuel won't start in Buffalo's season finale at New England because of a small tear in a left knee ligament that will not require surgery.
Coach Doug Marrone revealed the nature of Manuel's injury for the first time after practice Friday. Backup Thad Lewis will start Sunday.
''The decision process was injury-related, meaning that he was not able to do the things at 100 percent that, in my opinion, we need to do to win the game,'' Marrone said. ''So at the end of the day, I made the decision to put him out there for no other reason because I thought Thad would give us the best chance to win this game with EJ's injury not progressing.''
Marrone said Manuel has a ''small tear'' in his lateral collateral ligament, which the first-round draft pick hurt in a 27-20 win at Jacksonville on Dec. 15. The tear is regarded as a minor knee injury.
Lewis will start after taking all team snaps in practice Friday. Manuel could still be active and is listed as questionable.
The Bills (6-9) have already been eliminated from playoff contention but have a chance to win three straight for the first time since opening the 2011 season 3-0. The Patriots (11-4) have already clinched the AFC East and can secure a first-round bye.
The injury is the latest setback for Manuel, who is 4-6 this season. He missed four straight games after spraining his right knee in a 37-24 loss at Cleveland on Oct. 3. Manuel also missed the final two preseason games after hurting his left knee.
It's a setback for Marrone as well, who a week earlier had said he was ''110 percent'' confident Manuel would play against the Patriots.
Marrone began backing off that comment Monday, when he declined to announce a starter.
Manuel and Lewis split practice time Tuesday and Thursday, before Marrone determined the injury was limiting Manuel's lateral mobility.
Lewis is listed as probable because of an injury to his left, non-throwing shoulder, which he hurt in a 19-0 win against Miami last weekend. He has a 2-2 record and has thrown for three touchdowns and three interceptions since his promotion from the practice squad in early October.
''I feel very fortunate. I'm excited about the challenge,'' Lewis said. ''It's just another opportunity to go out and make the best of it and help this team get a win.''
The Patriots will be playing Lewis for the first time, after facing Manuel in their season-opening 23-21 road win.
''I know he's been playing good. I know he throws the ball down the field,'' Patriots cornerback Aqib Talib said. ''They get a lot of explosive plays when he's in the game, because he's not afraid to throw the ball down the field.''
Against Miami, Lewis completed a 57-yard pass up the left sideline to Robert Woods despite Buffalo being backed up inside its own 10.
The Patriots are expected to play without safety Devin McCourty, who hasn't practiced since sustaining a concussion in a 41-7 win at Baltimore on Sunday. That opens the door for rookie Duron Harmon to start.
The Patriots will face a Bills running game that ranks second in the NFL with 2,138 yards, led by C.J. Spiller and Fred Jackson.
''They do have a lot of weapons,'' Harmon said. ''So we know we're going to have our hands full.''
The Bills placed safety Aaron Williams on injured reserve and promoted receiver Cordell Roberson off the practice squad. Williams had already been ruled out because of a rib injury.
Roberson provides the team with depth at receiver with starter Stevie Johnson missing his second straight game. Johnson has been excused after the death of his mother, whose funeral was held Friday in Northern California.
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