Packers pass rusher Micah Parsons has been dealing with an L4/L5 facet joint sprain in his back and he may receive a facet injection before Sunday’s game against the Detroit Lions if needed to help him play, sources told ESPN’s Adam Schefter on Monday.

Before trading Parsons last week, the Dallas Cowboys prescribed him a five-day course of prednisone, an anti-inflammatory corticosteroid to help him recover from back tightness. They also had him on a physical therapy program.

Parsons has been practicing this week, and he is trying to play Sunday, although one source told Schefter it still is not certain if he will.

The Packers traded two first-round draft picks and defensive tackle Kenny Clark to the Cowboys last Thursday to acquire Parsons. Green Bay then signed him to a four-year, $188 million contract extension that includes $120 million fully guaranteed at signing and $136 million in total guarantees, making him the highest-paid non-quarterback in NFL history, sources told ESPN.

The move occurred after a training camp hold-in when Parsons sat out of Cowboys practices because of back tightness.

Parsons flew to Green Bay on Friday, passed his physical and signed his contract. He picked No. 1 for his jersey, becoming the second Packers player to wear that number and first since Curly Lambeau in 1925-26.

ESPN’s Rob Demovsky contributed to this report.