Kyle Shanahan says it is possible Reuben Foster could miss the 2017 season.

San Francisco 49ers coach Kyle Shanahan acknowledged it is possible that rookie linebacker Reuben Foster could miss the 2017 season due to shoulder problems, but described it as the "worst-case scenario" in an interview with KNBR on Thursday.

The 49ers selected Foster with the 31st pick in the NFL draft after Foster's stock sunk on draft day. ESPN's Adam Schefterreported that Foster's surgery on his right rotator cuff concerned NFL teams.

"Our doctors felt good about his shoulder. They thought it was recovering well, they didn’t have the same report a lot of other teams did. [...] The worst-case scenario is the shoulder doesn’t heal correctly, and you’ve got to do it again,” Shanahan said. "When you have to do it again, you've got to get another surgery, and it would be tough to play this year."

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Foster won the 2016 Butkus Award as the nation's top linebacker at Alabama. He recorded 115 tackles and 13 tackles for loss on the season.

Sports Illustrated's Chris Burke ranked him second on his NFL draft big board prior to the draft.