Weston Hodkiewicz

USA TODAY NETWORK-Wisconsin

The Green Bay Packers still don't know what they have in Jerel Worthy and it doesn't appear they'll be getting answers anytime soon.

Packers coach Mike McCarthy confirmed on Saturday that the third-year defensive lineman is out indefinitely with a lower back injury. He was placed on the team's non-football injury list, which means Worthy sustained the injury while he was away from the team in the offseason.

If it was a football-related injury, he would've been declared physically unable to perform like last season when he was recovering from a torn anterior cruciate ligament suffered in the 2012 regular-season finale.

Packers defensive line coach Mike Trgovac has said repeatedly this was an important offseason for Worthy. He was activated off PUP last November, but only played nine defensive snaps in two games with one tackle.

The Packers drafted Worthy in the second round of the 2012 draft to help the team's pass rush, but he managed only 14 tackles and 2½ sacks in 14 games his rookie season before tearing the ACL.

He missed the start of organized team activities due to his grandmother's death, but still didn't participate in any on-field drills during the offseason program once he returned to the team.

The outlook is more promising for outside linebackers Mike Neal (core/abdomen) and Nick Perry (foot/knee), who were placed on PUP but are "close" to a return, according to McCarthy.

Perry missed five games last season with a broken foot, but played in the team's final six games (including playoffs) despite fellow outside linebacker Clay Matthews saying he probably shouldn't have. He's since sat out all of the offseason practices.

"We definitely have plans for both Mike and Nick to be involved with the defense in certain schemes as well as personnel," Matthews said. "So anytime we can get them back, the sooner the better, it will be greater for our defense. … We need healthy players out here, and those are two guys who have a unique skill set that's only going to help our defense out."

Neal played in all 16 regular-season games for the first time in his career last season and was a full participant in the offseason program. Coming into camp, he said he felt fine up until the point of running.

"I feel alright. I don't feel bad, I mean I can't speak bad about it," Neal said. "A little sore than normal, but, that's expected sometimes when you come off an offseason. But I feel pretty good though."

Defensive lineman Letroy Guion (hamstring) joined Worthy on the non-football injuries and receiver Jeff Janis was absent at practice due to an illness.

Right guard T.J. Lang attended practice, but was mostly limited due to a shoulder injury. Don Barclay took first-team reps in his place,