Sources - Packers' Micah Parsons has joint sprain in his back - ESPN

GREEN BAY, Wis. — New Green Bay Packers defensive end Micah Parsons has been dealing with an L4/L5 facet joint sprain in his back and he may receive an 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 practiced with the Packers on Monday for the first time and according to several players at practice, he was a limited participant.

More clips from Micah Parsons' first day on the field in Green Bay, beginning with a little chat with his Penn State teammate Rasheed Walker. pic.twitter.com/ZqiMfc9Eg9

Parsons is trying to play in Sunday's regular-season opener against the Lions at Lambeau Field, although one source told Schefter it still is not certain if he will. If he plays, he would do so eight days after he was traded to Green Bay for two first-round picks and defensive tackle Kenny Clark.

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.

There was added energy to practice and an increased buzz in the locker room on Monday. Shortly after the trade made news, left tackle Rasheed Walker — a college teammate with Parsons at Penn State — posted on social media that the Packers were going to win the Super Bowl