FRISCO, Texas (AP) — Dallas Cowboys rookie defensive lineman Marshawn Kneeland is recovering from a season-ending right knee injury but will undergo surgery that could keep him out four to six weeks, according to a source.

An MRI on Monday revealed that the anterior cruciate ligament is intact, but he will require arthroscopic surgery for a torn meniscus. If he had suffered a torn ACL, his season would have been over. Assuming Kneeland’s surgery and rehab go well, he could return from a stint on injured reserve in mid-November.

Despite the good news, there will be an impact on the Cowboys’ defensive line, which could result in Micah Parsons being out another week with a high left ankle sprain, while DeMarcus Lawrence is on the injured list due to a Lisfranc injury in his right foot and can also be expected to return in mid-November.

Kneeland was injured on the fourth defensive play of the Cowboys’ 20-17 win over the Pittsburgh Steelers when he tackled quarterback Justin Fields. He was helped into the blue medical tent before being taken to the changing room for further examination and did not return.

The Cowboys used Kneeland and Chauncey Golston as starters in place of Parsons and Lawrence and turned to Tyrus Wheat and Carl Lawson after Kneeland’s injury. Wheat and Lawson had a half sack against the Steelers and three quarterback hurries.

After the game, coach Mike McCarthy said they worked with a few linebackers at that point against the Steelers in case another injury occurred.

Lawson has been left off the practice squad for the past three games but would now need to be added to the 53-man roster to be eligible to play again. It’s possible the Cowboys will look to bolster their position with at least one practice squad addition if Kneeland is out.

The defensive end group has been affected by injuries since the start of training camp. Sam Williams, who was expected to be the Cowboys’ third pass rusher after Parsons and Lawrence, suffered a torn ACL at the end of the season in one of the first training sessions in Oxnard, California.