ALLEN PARK -- The Detroit Lions opened training camp on Friday without three players. Offensive lineman Leroy Harris and wide receiver Devin Thomas were placed on the physically unable to perform list while defensive end Ronnell Lewis was designated for the non-football injury/illness list.

Harris, who signed with Detroit in June, is still recovering from an ACL tear suffered last season. Lions coach Jim Schwartz said Harris is doing well, even participating in the team's mandatory conditioning test, but the training staff wanted to wait to see how his body responded before returning him to action.

"If we can make sure that it's not going to be sore the next day, we can get past that, we can get him on the practice field," Schwartz said.

As for Lewis and Thomas, both players passed the conditioning test, but their bodies didn't respond well after.

"We just wanted to give them a couple extra days to round themselves into shape," Schwartz said. "Ronnell has always been one of those guys that needs a lot of IVs and stuff like that. You take the approach of rather than putting them right out there, maybe pulling a hamstring, let's monitor them and let's see where it is."

Louis Delmas (knee), Ryan Broyles (ACL) and Nate Burleson were all cleared to practice. Delmas was limited in his first offseason action, only taking part in individual drills.

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