FRISCO, Texas (AP) — Dallas Cowboys left tackle Tyron Smith has a torn left hamstring and could be sidelined for months, according to an ESPN report.

Smith was injured during 11-on-11 drills in practice Wednesday night when he went to engage linebacker Leighton Vander Esch about 5 yards downfield before crumpling to the turf. He walked off the field without help.

The team initially said on its website Smith had a knee injury and an MRI was planned. ESPN, citing unidentified sources, later reported the 31-year-old had a torn hamstring.

The eight-time Pro Bowler has been hampered mostly by back, neck and shoulder injuries in recent years. Smith has missed at least three games each season since 2016, including a career-low two games in 2020 before season-ending neck surgery.

The Cowboys were counting on Smith and five-time All-Pro right guard Zack Martin as the anchors on an offensive line that is young at the other three spots.

If Smith misses significant time, rookie first-round pick Tyler Smith could replace him. Tyler Smith has been working at left guard but was the starting left tackle at Tulsa. He missed both practices this week with an ankle injury.

Josh Ball, a fourth-round pick last year, has replaced Tyron Smith at times during training camp this year. Ball missed all of his rookie season with an ankle injury.

The defending NFC East champs, who lost a wild-card game at home to San Francisco in January, open the season at home Sept. 11 against Tom Brady and the Tampa Bay Buccaneers.