Indianapolis (6-4) played its way into playoff contention with four straight wins against teams with a combined 11-29 record before heading into last week's showdown at New England.
Now, the Colts are left trying to erase the memory of an embarrassing 59-24 loss to the Patriots.
Indianapolis, facing its first opponent with a winning record since a Week 2 win against Minnesota, had four turnovers, including two interceptions that were returned for touchdowns.
Luck completed 27 of 50 passes for 334 yards and two touchdowns with three interceptions - his first three-pick game since the season opener. Still, he broke Peyton Manning's NFL rookie record with his fifth 300-yard game.
``You realize it's just one loss,'' Luck said. ``It doesn't count any more or any less in the column and realize that we're still in a decent position, I think that some other teams would like to be in. Our goals are still obtainable.''
Rookie T.Y. Hilton looks for his third 100-yard receiving effort in four games after finishing with six catches for 100 yards and two touchdowns against the Patriots.
Indianapolis, which has yet to lose two straight this season, could be line for a big day against a Buffalo defense that ranks near the bottom of the league in yards (401.1) and points allowed (29.9).
While the Bills also have the worst run defense in the AFC, allowing 153.3 yards per game, it might not matter with the Colts' inconsistent ground game.
Donald Brown has been slowed by a knee injury and rookie Vick Ballard is averaging just 57.3 in his six starts after rushing for 72 yards on 16 carries against New England.
Buffalo's defense, however, is coming off one of its best performances, allowing a season-low 184 yards in a 19-14 victory over Miami on Nov. 15 that halted the team's three-game losing streak.
The unit should get a boost on Sunday with the return of defensive end
"If we can win these ballgames coming down the stretch, and get healthy to make a push for the playoffs, that's huge," Kelsay said.
The Bills (4-6) are on the fringe of the AFC playoff race, with three teams ahead of them competing for the conference's two wild-card spots.
They should be helped by the return of running back
The Bills' rushing attack, which ranks third in the AFC with 140.8 yards per game, has been key to the team's success.
Since the start of last season, quarterback
Buffalo will try to keep the Indianapolis defense reeling after it allowed season highs in points and yards (446) in the humbling loss to the Patriots.
"Last week, it was keeping the season alive, and it's the same thing now,'' Bills receiver
The Colts had won six straight against Buffalo before losing at Orchard Park in a meaningless season finale on Jan. 3, 2010, when playoff-bound Indianapolis rested Peyton Manning and others most of the game.