LAKE FOREST, Ill. — Chicago Bears safety Mike Brown will miss the rest of the season due to a calf injury, leaving the defense without one of its emotional leaders heading into Sunday's game at Houston that could decide whether they make the playoffs.

It's the fourth trip in five years to injured reserve for Brown, who left the game against Green Bay on Monday night. Losing him is a big blow to the Bears (9-6), who need to win or tie the Texans to have a shot at the NFC North title or a wild-card spot.

If they beat Houston, they would need Minnesota to lose to or tie the New York Giants to win the division, since the Vikings (9-6) hold the tiebreaker. And to get the wild card, they would need losses or ties by Dallas and Tampa Bay.

If the Bears tie Houston, they could still win the division if Minnesota loses, or capture the wild card if Dallas and Tampa Bay go down.

The oft-injured Brown started 15 games this season and had 101 tackles, two interceptions, two tackles for losses and one sack before his latest season-ending injury. He ruptured the anterior-cruciate ligament in his left knee in last year's opener, missed the final 10 games in 2006 with a foot injury and suffered a season-ending Achilles' injury early in the 2004 season. Even when he made the Pro Bowl in 2005, Brown missed the final four regular-season games with a calf injury before returning for the playoffs.

With Brown out the Bears brought back safety Cameron Worrell, who spent his first four seasons with them before signing with Miami in 2007. Worrell signed with the New York Jets before this season and was placed on injured reserve on Aug. 30 before reaching an injury settlement three days later.