Per the Official Site:
Gibbs also updated the injury status of Clinton Portis, saying the veteran running back has developed tendonitis in his knee.
All the gruesome details on tendinitis are at wikipedia, like this nugget:
Due to their highly specialised ultrastructure, low level of vascularization and slow collagen turnover, tendons and ligaments are very slow to heal if injured, and rarely regain their original strength. Partial tears heal by the rapid production of disorganized type-III collagen, which is weaker than normal tendon. Recurrence of injury in the damaged region of tendon is common.
Encouraging stuff. Portis' specific case, though, is no big shakes:
Asked about the health status of Portis, Gibbs revealed that the sixth-year running back has developed tendonitis in his knee. Portis visited with Dr. James Andrews, the team's medical consultant in Birmingham, Ala., on Wednesday.
We'll keep a close eye on this.
The tendonitis in his knee flared up last week. It is not considered serious.
"He has had some soreness in his knee, but he said he could run and work out on it," Gibbs said. "He's on his weight [training] program. We'll see how the running goes. We'll see how quickly we can get him back.
"The main thing now is to get it taken care of now. What we don't want is this when we go to camp."
Portis has been continuing to rehab from offseason shoulder surgery. The shoulder is holding up well through the rehab, team officials said.
AOL Fanhouse, For a Guy Not Injured Very Much, Portis Has a Bunch of Injuries