ORCHARD PARK, N.Y. (AP) Jim Schwartz benefitted from having Matthew Stafford and Calvin Johnson on his side for five years.
Now he has to figure out how to stop them.
Schwartz is in his first season as the Buffalo Bills defensive coordinator, and the last thing he wants to discuss his time as head coach of the Detroit Lions, which ended with him being fired after last season.
But it's an unavoidable topic this week as Buffalo (2-2) prepares to play at Detroit (3-1) on Sunday.
''It's about the same as any week,'' Schwartz said Friday. ''I've been a visitor there before, so I know where the visitor's locker room is, in addition to the home locker room.''
Schwartz had a 29-51 record in his five seasons in Detroit and led the Lions to the playoffs in 2011. He was previously the defensive coordinator in Tennessee for seven seasons.
''Whether it's the Lions, whether it's any other team, everybody has connections in this league,'' Schwartz said. ''Every coach has coached somewhere else. Everything else, it doesn't play into the game.''
This will be the first time, however, Schwartz has to worry about defending Johnson.
''I don't think anybody has really figured out a plan for it,'' he said. ''I've seen firsthand all of the schemes people use to try to take him out of a game, but he's still productive regardless.''
Schwartz was booed during his final home game last season, a 23-20 loss to the Giants that eliminated the Lions from playoff contention.
He said he is not concerned with how the fans will greet him Sunday at Ford Field.
''It doesn't matter,'' he said. ''It's about the game. That's certainly not important.''
Bills linebacker Brandon Spikes said Schwartz hasn't addressed his return to Detroit this week, but players are aware of it and motivated to prove something on his behalf.
''I can relate. The place I was at, everything didn't work out at the end,'' said Spikes, who signed with the Bills in the offseason after five seasons with the New England Patriots. ''Same thing with him. He wants to show up and let them know they made a mistake. Actually, I feed off of that.''
Schwartz became the Bills' defensive coordinator after Mike Pettine left to coach the Cleveland Browns.
The Bills' defense finished 10th in the NFL in yards allowed in its first season under Pettine and ranked second in the league with 23 interceptions and a franchise-record 57 sacks.
Buffalo has continued to pressure the quarterback and create turnovers under Schwartz. Through the first four games, the Bills have compiled 11 sacks, five interceptions, and three fumble recoveries.
The run defense this season has been much improved. The Bills rank third in the league in allowing 71.5 rushing yards per game, and second in the league in allowing 2.9 yards per carry. Each of their first four opponents have been held under 90 yards rushing.
Last season, the Bills allowed 128.9 yards per game (ranking 28th in the league) and 4.4 yards per carry (23rd) and held opponents under 90 rushing yards just three times.
The Bills sought to improve their run defense by adding free agent linebackers Spikes and Keith Rivers to a front four that includes Pro Bowlers Kyle Williams, Mario Williams and Marcell Dareus.
But coach Doug Marrone said Schwartz has helped the Bills improve against the run by switching from a 3-4 base alignment to a 4-3 scheme.
''You have an extra player there at the second level,'' Marrone said.
The Lions' defense has been even better under new head coach Jim Caldwell and defensive coordinator Teryl Austin.
Detroit has the NFL's top-ranked defense, allowing 267.3 yards per game. The Lions rank second against the pass (186.5 yards per game), sixth against the run (80.8 yards per game) and fourth in scoring defense (15.5 points per game).
Caldwell said he doesn't think Schwartz's return will be a factor in Sunday's game.
''This is a transient league,'' he said. ''I just think it happens so often, it's really not a big issue.''
NOTES: Bills DT Kyle Williams and OLB Nigel Bradham were both limited participants in practice Friday due to knee injuries and listed as doubtful to play Sunday. LG Chris Williams (back) and WR Marcus Easley (knee) are out. . The Bills re-signed WR Naaman Roosevelt to the practice squad and placed WR Caleb Holley on the practice squad/injured list. Roosevelt played in 16 games for the Bills from 2010 to 2011.