First place in the NFC North is at stake Sunday, and the Green Bay Packers will be nowhere in the vicinity.
Instead, it's the Bears, one of seven 3-0 teams, against the Lions at Ford Field. A victory for Chicago would give it a stranglehold on the division through one-fourth of the schedule.
The Bears have been impressive under new coach Marc Trestman, showing a knack for clutch plays on both sides of the ball. They have a league-high 11 takeaways, are making good decisions, and Devin Hester is averaging 38 yards a kickoff return.
But they also have some injuries, with defensive end Henry Melton (knee) gone for the season and star cornerback Charles Tillman hobbled but saying he will play. Tillman normally would match up with the Lions' top threat, receiver Calvin Johnson.
"He's a big, strong, physical corner," Johnson said of Tillman. "He's smart. He's seen a lot of football, so he understands some of the concepts probably that we do on offense, so we've got to throw different things at him to get him off balance."
Detroit (2-1) is winning the close ones — the Lions have outscored the opposition by only 13 points. Their passing attack is second in the league, but just lost a key piece when receiver Nate Burleson was injured in a car accident.
The Lions got some good news: Running back Reggie Bush has recovered from the left knee injury that sidelined him in last week's win over Washington.
"He's a very valuable part of our offense and he affects the way defenses play us," coach Jim Schwartz said. "If we can get him back on the field, that will be a big plus for us."
Week 4 began with San Francisco's 35-11 rout of St. Louis in which the 49ers (2-2) had five sacks, limited the Rams (1-3) to 18 yards on the ground and got 153 yards rushing and a touchdown from Frank Gore.
On Sunday, it's New England at Atlanta, Seattle at Houston, Pittsburgh vs. Minnesota in London, the New York Jets at Tennessee, Philadelphia at Denver, Dallas at San Diego, the New York Giants at Kansas City, Cincinnati at Cleveland, Baltimore at Buffalo, Indianapolis at Jacksonville, Washington at Oakland, and Arizona at Tampa Bay.