PITTSBURGH — Steelers center Nate Herbig is expected to be sidelined for a significant amount of time with a torn rotator cuff, a source confirmed to ESPN, paving the way for the team to start rookie center Zach Frazier.

Herbig, a 26-year-old interior offensive lineman, worked primarily at center with the first team line throughout training camp before sustaining the injury last week. Coach Mike Tomlin acknowledged Herbig’s injury following the Steelers’ preseason loss to the Buffalo Bills on Saturday night, but said Herbig was seeking a second opinion.

Frazier, a West Virginia product, was selected in the second round of April’s draft and started in Herbig’s place against the Bills.

“Nate’s got an injury that’s being continually evaluated,” Tomlin said when asked about Herbig’s status postgame. “I think he’s getting a second opinion. I want to wait to that. I’ll give you guys some information probably the next time we come together, but I was largely satisfied with the work that I saw from Zach.”

Though Frazier was drafted to eventually be the team’s starting center, the injury to Herbig, who was active for all 17 games last season and played 156 snaps, depletes the team’s interior depth. As a position-flexible lineman, Herbig was the line’s top reserve last season and figured to play a similar role this season.

The Pittsburgh Post-Gazette first reported Herbig’s injury.

With Herbig’s injury, 2023 seventh-round pick Spencer Anderson and 2024 fourth-round pick Mason McCormick are the most likely candidates to fill out interior depth behind Frazier and guards Isaac Seumalo and James Daniels.

Frazier played one series with quarterback Justin Fields in the Steelers’ first preseason games after fumbles on the snap between Herbig and Fields during the first two series. Frazier, who started 37 consecutive games at center during his college career, earned solid reviews from coaches and teammates during training camp for his work ethic and physicality.

“Zach’s a hard worker,” Fields said Thursday. “He’s humble, doesn’t say much, but boy, he works. So glad to have him on the o-line and I mean, he’s a strong, strong boy.

“He’s smart too, so it’s great to see a rookie that young, that smart controlling where the protections are going. I’ll flip a protection, and he already had done it before I’ll even do it sometimes. So just seeing that from him, knowing how smart he is, is definitely a good thing to see.”