The injury hits just keep coming for the Pittsburgh Steelers, and this time the concern is right in the middle of the offense.

As the team prepares for a tough Week 16 showdown with the Detroit Lions, starting center Zach Frazier was listed as did not participate in the latest practice due to a triceps injury, and that’s a red flag that the Steelers can’t really afford right now.

Frazier’s absence is especially alarming because it’s new.

He was a full participant the previous day, which suggests something popped up suddenly. The severity isn’t clear yet, and his status will likely hinge on how, or if, he’s able to go in the final practice before kickoff.

In the meantime, backup Ryan McCollum has stepped in for first-team reps. While the staff likes his effort and intelligence, there’s no sugarcoating the drop-off. Frazier is already viewed as one of the top centers in the NFL, anchoring both the run and pass game and handling line calls at an elite level.

Losing that against a physical Lions front would be a major problem.

And it’s not just Frazier. The Steelers could realistically be down three starting offensive linemen. Left tackle Broderick Jones is already out for the regular season, with Dylan Cook filling in admirably but under constant pressure.

At left guard, veteran Isaac Seumalo is banged up again, with Spencer Anderson likely next man up if he can’t go.

All of this is happening as the Steelers cling to their fading postseason hopes and try to stabilize an offense that’s already under the microscope.

Frazier says he believes he can play. Steelers fans will be holding their breath until the final injury report tells them whether belief turns into reality … or into another brutal blow up front.