Rookie Mike James, who was the initial replacement for Martin, had surgery Thursday, Schiano said. James fractured his ankle early in Monday night's game against Miami.
Martin suffered a torn labrum while attempting to catch a pass in an Oct. 20 game against Atlanta.
Both players have been placed on injured reserve and Schiano has said he's confident they will recover in time for next season. Without their top two running backs, the Bucs are turning to Brian Leonard and Bobby Rainey.
In other injury news, defensive end Da'Quan Bowers, who has been experiencing concussion-like symptoms, still was not cleared to practice Friday. Schiano said Bowers could be out for Sunday's game with Atlanta.
"It's not definite, but the longer we wait the more we're headed in that direction,'' Schiano said.