The injury is another knock for Martin, who missed the first three games of the season stemming from last year's failed drug test.
Since the ban was lifted, Martin has rushed 112 times for 343 yards and two touchdowns as Tampa Bay's bell cow. He's also managed seven receptions for 60 yards.
But now that Martin is banged up again a season after appearing in just eight games, the Bucs will have to pivot back to their contingency plan.
That means Jacquizz Rodgers should eat up early-down work, with Charles Sims operating as the third-down pass-catching specialist.