Dallas Cowboys left tackle Tyron Smith will undergo surgery Friday to reattach his left hamstring, according to ESPN's Ed Werder.
Smith is expected to be sidelined for a minimum of three to four months.
The news comes after NFL Network's Ian Rapoport reported Thursday that Smith will undergo surgery for an avulsion fracture in his left knee.
ESPN's Adam Schefter added that Smith's hamstring tore and came off the bone and that he would be sidelined indefinitely, unlikely to return before December.
The 31-year-old exited Wednesday's practice early, and a concerning video showed him grabbing his knee after making minimal contact with another player. He walked off the field under his own power alongside trainers.
Cowboys owner Jerry Jones addressed Smith's injury while meeting with reporters Thursday:
"It's a big disappointment, none more so than for Tyron himself," Jones said. "... Immediately that battle cry is 'let's get it done early in the season,' because when Tyron gets back, we'll be that much stronger.
"We want it pushed up there where we're in the lead. When we get there healthy, we can make that run in the playoffs. This doesn't diminish that hope"
Smith has a pretty lengthy injury history and he had been dealing with an ankle ailment suffered in joint practices with the Denver Broncos last week.
Last season, he was often not a full participant in practice because of knee and ankle injuries, which limited him to just 11 games. He also missed time due to a bout with COVID-19.
The eight-time Pro Bowler's latest injury is quite concerning for the Cowboys as they don't have much depth at the position. Rookie Tyler Smith, Josh Ball, Matt Waletzko and Aviante Collins could all see more playing time in his absence.
Dallas opens the season on Sept. 11 against the Tampa Bay Buccaneers at AT&T Stadium.