LAKE FOREST, Ill. - Chicago Bears safety Mike Brown hobbled into the locker room on crutches, his right foot covered by a large cast and his season for the unbeaten Bears over.

One of Chicago’s most important defenders, Brown was put on injured reserve Thursday after surgery a day earlier to repair ligament damage in the foot. He was injured in a pileup during Monday night’s victory over Arizona.

It’s the third time in as many seasons Brown’s been forced to the sidelines by a different leg injury. With long hours of rehab ahead, the Pro Bowl safety was initially feeling sorry for himself.

“It’s going to be extremely tough. I was having a pity party and my wife ended that pretty soon,” Brown said.

“She told me to stop feeling sorry for myself about an hour into my pity party. I got over it pretty quickly. It stinks, man. I love playing the game.”

Brown returned a fumble for a TD to help the Bears start their 24-23 comeback win Monday night — his franchise-best seventh career defensive touchdown — and then was hurt early in the final quarter. He said he wouldn’t be out of the cast for about 10 weeks, and the Bears will turn to Todd Johnson to take over his spot.

Brown missed 14 games with a torn right Achilles’ tendon in 2004, and the injury-ravaged Bears went 5-11. Brown missed the final four regular-season games a year ago with a calf injury and then was forced out of a playoff loss to Carolina in the second quarter when he reinjured it. In his first four NFL seasons he started 47 of 48 games.

“I know people are going to say, ’injury-prone,”’ Brown said. “All the injuries that I’ve had, they don’t relate to each other. I just happened to be stuck in a pile that no player wants to be stuck in that situation. It’s a bad situation to be in, I couldn’t get my foot up out of the turf, all the weight came down. I’m just fortunate it’s just my foot and not something like my knee is gone and ligaments and all that.”

Johnson, who has 12 career starts, including 10 in Brown’s spot two years ago, is a hard-hitter, but what the Bears will miss is Brown’s leadership and his uncanny ability to always be around the football.

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“You can’t really replace his leadership and his presence,” Johnson said Thursday. “He spoke to the defensive backs and said the train has to go on.”

Brown’s 14 career interceptions include two he returned for game-winning overtime touchdowns in back-to-back weeks during the 2001 season.

“He’s had injuries before and he knows how to come back from them,” Bears coach Lovie Smith said, adding that Brown will be around to mentor other defensive backs.

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Brown’s not sure what his latest injury might mean for his career in Chicago — he signed a six-year extension in 2003 — but he’s confident he’ll be on the field next season.

“I know I can come back and play at a really, really high level. I feel like I’m one of the best safeties in the league when I’m healthy, playing. That’s my goal, to get healthy so I can continue to play at that level,” he said.