Alabama junior linebacker Terrell Lewis suffered a torn right ACL last week while training, Crimson Tide coach Nick Saban announced Tuesday.

"Terrell Lewis suffered a torn right ACL last week while training," Saban said in a statement. "He underwent successful surgery today, and a timeframe for his return is unknown at this time."

Last year, Lewis missed 10 games after suffering an elbow injury against Florida State in the Tide's 2017 season opener. He finished the season seeing time in four games with one start and totaled 16 tackles, including two for loss, one sack and a pass breakup during his sophomore campaign.

Finally healthy this spring, the former 4-star recruit participated in all of Alabama's 15 practices, including the A-Day Game, where he registered one tackle. Despite his low totals, he felt good about his spring campaign and was entering a junior season that could be his last in Tuscaloosa, Ala. -- because of his projected NFL potential in a year's time.

"I feel like I haven"t scratched the surface yet," Lewis said. "I still feel like I haven't done a lot for this program yet, so I feel like the best is yet to come."

Now, however, whether or not Lewis even sees the field in 2018 will be in question. Tight end Miller Forristall suffered an ACL injury in Alabama's Week 3 game against Colorado State and did not return to the field until this spring. With the new redshirt rule, though, Lewis could play in only four games -- like last year -- and not lose a year of eligibility.

With Lewis' injury, Alabama is left with four experienced players at outside linebacker, including Christian Miller, Anfernee Jennings, Jamey Mosley and Christopher Allen. The Tide also welcomed Jarez Parks during the team's preparation for the College Football Playoff, as well as summer enrollees Eyabi Anoma and Cameron Latu.

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UA's linebacking corps suffered several injuries last year, including losing Lewis, Miller and Jennings at different times. But that opened the door for younger players to earn valuable reps.

"It definitely made a lot of guys realize that you never know when your time is up," Lewis said. "I know Christopher Allen, for sure, he went from a guy that was trying to learn and follow ... and then is really active now as far as questions, like 'What would I do here?' and stuff like that. It just changes your perspective on how you should go about practice and stuff like that."

On Monday, Saban also announced the dismissal of linebacker VanDarius Cowan, who has spent time with the outside linebacker in the past.

Alabama will open preseason camp early next month and opens the season against the Lousiville Cardinals on Saturday, Sept. 1, in Orlando, Fla.

Contact Charlie Potter by 247Sports' personal messaging or on Twitter (@Charlie_Potter).