PITTSBURGH (AP) — Pittsburgh Steelers outside linebacker T.J. Watt underwent surgery to repair a partially collapsed lung sustained during a dry-needling session and will miss Monday’s visit by Miami.

J.J. Watt, T.J. Watt’s older brother, posted on X that T.J. had the surgery on Thursday.

Steelers head coach Mike Tomlin said after practice Friday that T.J. Watt was home resting comfortably but would be unavailable when Pittsburgh (7-6) hosts the surging Dolphins (6-7).

Asked if Watt could be out for an extended period, Tomlin said he hadn’t looked beyond this week.

Watt was hospitalized on Wednesday after reporting what the club described as “discomfort” while being treated by Steelers medical staff at the team facility. J.J. Watt said T.J. was having a dry-needling session at the time.

Dry needling is a treatment used by physical therapists and acupuncturists to treat pain and movement issues, according to the Cleveland Clinic. The medical professionals insert needles under the skin to target trigger points in muscles.

Watt has been a fixture on the Steelers’ defense for nearly a decade. He was on the injury report last week with a toe problem, but that didn’t stop him from making his 56th straight regular-season start.

Tomlin said Thursday that Watt had not complained of any issues in his chest at any point this season. The coach added he had “no idea” about the details of Watt’s dry-needling session but added he was not in a position to “dispute something said by someone close to him.”

A seven-time Pro Bowler and the 2021 NFL Defensive Player of the Year, the 30-year-old Watt has seven sacks this season for the Steelers, who hold a one-game lead over Baltimore for the AFC North lead with four weeks remaining.

Pittsburgh has struggled historically without Watt in the lineup, most notably in 2022 when the Steelers went 1-6 while he recovered from a pectoral injury.

Nick Herbig will start in place of Watt against Miami. Herbig has played exceptionally well at times during his third season. His 6 1/2 sacks are a career-best and rank second on the team, trailing only Watt.