Shanahan confirms high-ankle sprain for Reuben Foster, who could miss a month

On Monday, Ian Rapoport of NFL Network reported that San Francisco 49ers rookie linebacker Reuben Foster suffered a high-ankle sprain based on a preliminary diagnosis and he is very likely to miss time. Head coach Kyle Shanahan later confirmed that report, saying Foster did indeed suffer a "typical high-ankle sprain" but was unsure about the timetable for a return.

"[Head athletic trainer Jeff Ferguson] didn't give me an exact date because we don't know exactly with Reuben," Shanahan said. "We're going to put him in a boot here for a little bit but those tend to be a month, a little more, but I can't put exactly a date on it. That's my experience with high-ankle sprains."

Shanahan also stated that he was not given a grade regarding the injury. The head coach was also asked what he thought of Foster's performance prior to the injury.

"He was playing well," Shanahan answered. "He was around the ball a ton. Got close to a pick. Was near another one. Made a good play in the screens right before he got hurt. Ripped the ball out there. Got it loose at the end. [Panthers running back Christian] McCaffrey's knee was down but he was playing well."

Foster was replaced in the game by Ray-Ray Armstrong, whom he beat during training camp for the starting weak-side linebacker job.

"I thought Ray-Ray did a solid job," Shanahan said. "He stepped up, came in, played real hard, didn't lack any effort. He was around the ball, made some plays."

The injury could have been a lot worse. During initial replays, Foster's injury appeared to be a lot worse and possibly season-ending.

"They thought at first, possibly tibia and stuff and they came out and told me at halftime that was a negative but he wasn't good enough to go back into the game," Shanahan said after the game.

Following the injury in the first quarter, Foster was carted off of the field and taken to the locker room for X-rays. He didn't feel it was that serious. After returning to the sideline, Foster campaigned with the 49ers medical and training staff to let him back into the game. Following the 23-3 loss, Foster insisted he would be ready for the 49ers' September 17 road game against the Seattle Seahawks.

"I wanted to go back out there," Foster said. "It was loosening up. It doesn't hurt anymore. I'll be good against Seattle."

As revealed on Monday, that will not be the case. Prior to the injury, Foster had three tackles, one pass defense, and nearly had an interception.

According to Shanahan, Foster was the only "big" injury that resulted from the 49ers' Week 1 game. That means other injuries, like the one to fullback Kyle Juszczyk, were minor.

"A bunch of guys were sore," Shanahan said. "Some wear and tear. Typical Monday. But Reuben was the only big one."