According to defensive coordination Dom Capers, Woodson sustained the injury while trying to intercept a third-down pass on the Rams' second-to-last possession. Woodson stayed in the game and helped make the fourth-down stop, then wasn't on the field for the Rams' final drive of the game, which resulted in a touchdown.
"He's obviously an integral part of everything we do," Capers said.
McCarthy and Woodson talked on Monday morning, and Woodson told him he was a "little nervous" about the injury on Sunday night. Woodson had X-rays on Monday and McCarthy was alerted to the results during a staff meeting.
It's the same injury as the one he sustained in the Super Bowl, though "not as significant," McCarthy said. The Packers have no plan to put Woodson on season-ending injured reserve and are prepared to go a man short on the roster until Woodson can return.
"Well, just knowing Charles, all I have to go on is him in the past," Capers said. "He's been doing this long enough that he knows his body and he's kept himself in tremendous condition or he wouldn't be playing at his age right now and be able to play at the level he's played. I think that he'll do all the rehab things and we'll just have to wait and see what our medical people say in terms of how fast he will be back. He's a guy that I wouldn't put anything past him in terms of being able to come back."
Woodson, playing safety with the base defense and his usual role as nickel cornerback in the sub packages, ranks fifth on the team with 38 tackles. He had one interception, pushing his career total to 55, good for 19th in NFL history and second behind Ed Reed (59) among active players.
The two challenges are replacing Woodson's on-the-field production and his leadership. Beyond the big plays in the passing game, Woodson's calling card has been as a physical, secure tackler in the run game and as a blitzer when he plays at the line of scrimmage. He's also one of the team's unquestioned leaders and the team's emotional heart beat.
"It's a bigger challenge. I mean, we're talking about Charles Woodson. There's no question about that," McCarthy said, noting Woodson's leadership ability. "The reality is, we fully expect and will play for the next individuals to step up and continue to play better defense. That's our goal every week, regardless of how we line up. This has been a hard couple weeks for us. We've lost players to season-ending injuries (and) obviously Charles' injury is significant. Our younger players are prepared and we'll move forward and we'll have a good plan for Jacksonville.
At Woodson's spot in the nickel package, he'll be replaced by impressive rookie Casey Hayward. Hayward had been the other slot cornerback in the dime package. Jarrett Bush and rookie safety Jerron McMillian are the candidates there. At safety, Jerron McMillian and M.D. Jennings will share time with Morgan Burnett.
Hayward had an interception in an excellent starting debut against the Rams, when he replaced Sam Shields (shin/ankle) as one of the outside corners. McCarthy is hopeful Shields can practice on Thursday; if not Thursday, McCarthy said he'd feel comfortable playing Shields if he only can practice on Friday.
Either way, Davon House could be in line for his first NFL start. House, who was the front-runner for the starting job until injuring a shoulder at San Diego in the first preseason game, played corner in the dime package. Unofficially, he gave up three completions in seven targets. He had a big pass breakup on fourth-and-2 from the Packers' 14-yard line early in the second quarter.
"You have to be very happy with the way Davon House played in the game," McCarthy said. "Really, the one play you'd be critical of him was the touchdown – the finish on the play needed to be better. I thought he was extremely physical and he does an excellent job getting his hands on receivers. That was obviously the big question with him coming back from his injury. I thought he got off to a really good start. He'll have more opportunities as we move forward, especially this week against Jacksonville.