I read they had minor back spasms or something. nothing serious in the least from what I heard.
That's ESPN for you.
edit- from the camp report thread 3:
Call a chiropractor
Cornerback Al Harris, middle linebacker Nick Barnett and tight end Donald Lee experienced tightness in his back Tuesday morning. Barnett sat out the entire morning session, and Lee left the night practice early and did not return. In the locker room after the morning practice, Barnett said he wasn't concerned about his injury. "It's been tight for a week now, so (team trainers) decided to give it a rest for a little," Barnett said. "I don't think it's that big of a deal."
so..nothing serious...