T.J. Watt recently underwent arthroscopic knee surgery that is expected to delay his return to the Pittsburgh Steelers, sources told ESPN.

Watt, who already was recovering from a torn pectoral muscle, had the knee surgery to clean up a preseason injury that lingered into the regular season, according to sources. The star pass-rusher initially was expected to miss six weeks because of the pectoral injury suffered in Pittsburgh's season opener, setting up a potential return Oct. 30 against the Eagles.

But the knee surgery likely will push back Watt's return by at least another week or two, according to sources, meaning the reigning NFL Defensive Player of the Year now might not be back until after the Steelers' bye in Week 9. Pittsburgh hosts the Saints in Week 10 before a Week 11 road game against the Colts on Monday Night Football.

The Steelers will not rush Watt back and will be diligent in monitoring how both his knee and pectoral muscle respond. The team, however, no longer is counting on Watt to return before the bye week, according to sources.

Watt's arthroscopic knee surgery came during the same week that his brother, Cardinals defensive end J.J. Watt, went into atrial fibrillation and had to have his heart shocked back into its normal rhythm. The elder Watt ended up playing three days after his procedure, registering three tackles and two deflected passes last weekend during Arizona's victory over the Panthers.

The Steelers have struggled without Watt -- a cornerstone of their defense -- recording only three sacks during his absence over their past three games. Since Watt's rookie season in 2017, the Steelers are 0-7 when he doesn't play, including 0-3 this year as they head into the Sunday game in Buffalo against the Bills.