Saban said Sanders will be "out indefinitely" following surgery. He did not provide further details after the Crimson Tide completed their first full scrimmage of the preseason.
AL.com first reported that Sanders was hurt on the last play of Thursday's practice and would likely be out for the year.
Saban said earlier in the week that the 6-foot, 214-pound Sanders, who played at IMG Academy, had shown a lot of promise since arriving on campus as ESPN's No. 2-ranked running back prospect nationally in the 2019 signing class.
The loss of Sanders would put a dent in Alabama's running back depth. Josh Jacobs and Damien Harris are both now in the NFL after being drafted in the first and third rounds, respectively, earlier this year.
The Crimson Tide's leading returning rusher is junior Najee Harris, who was second on the team to Damien Harris with 783 rushing yards last season and a team-leading 6.7 yards per carry.
Alabama coaches are especially high on junior Brian Robinson Jr., who played in 15 games and rushed for 272 yards a year ago. His role will grow considerably this season. The Crimson Tide also brought in ESPN 300 running back Keilan Robinson of Washington, D.C., in this signing class.
In other injury news, Saban said defensive tackle D.J. Dale will likely miss about a week with a sprained knee. Linebacker Joshua McMillon also sustained "a potential knee injury" during Saturday's scrimmage which Saban called "concerning."
The Associated Press contributed to this report.