Tampa Bay Buccaneers rookie running back Charles Sims will undergo surgery Saturday to repair his injured right ankle, the team announced Friday.

Sims hurt his ankle during Tuesday's practice and was seen Thursday in a walking boot. He'll be out 12 to 14 weeks, nearly half the regular season.

The Bucs' third-round pick in May's NFL Draft, Sims was expected to back up starting running back Doug Martin this season. Backups Mike James and Bobby Rainey are expected to be elevated on the depth chart.

"Great feet, we drafted him because of what we saw, of course carrying the ball in between the tackles, but in the open field he can make you miss," Buccaneers head coach Lovie Smith said of Sims earlier in training camp. "He’s got excellent hands and the last couple of days he’s made a couple of really good cuts that brought a smile to all of our faces. Can’t have too many good running backs, Doug Martin made a couple of really good plays and you can talk about Bobby Rainey, Mike James, all of our running backs have.”

Sims is expected to be placed on injured reserve, with the designation to return, to start the year.