8:58 PM ET

According to sources, T.J. Watt had knee surgery that will delay his return to the PittsburghSteelers.

Sources say that Watt had knee surgery to clean up a preseason injury that lingered into the regular season. The star pass-rusher was expected to be out for six weeks because of the injury he sustained in the season opener.

According to sources, the knee surgery will push back Watt's return by at least another week or two, meaning he won't return until after the Pittsburgh's bye in Week 9. The Saints are in Week 10 and the Colts are in Week 11.

Watt will not be rushed back and will be monitored closely to see how he responds. Sources say the team doesn't expect Watt to return before their bye week.

Watt had a knee surgery the same week that his brother J.J. Watt had an arrhythmia scare. Three days after his heart procedure, the elder Watt played in Arizona's victory over the Carolinas, recording three tackles and two passes.

Watt has been out of the lineup for the last three games, and the Pittsburgh defense has not been as effective. TheSteelers are 0-7 when Watt doesn't play since he joined the team, including 0-3 this year, as they head into Sunday's game in Buffalo against the Bills.