Rivera underwent arthroscopic surgery on his right knee in early February. The surgery was timed to follow the season, in which he started all 17 games despite tears to medial collateral ligaments in both knees. Rivera also took time for the Pro Bowl before the surgery.
So far the guard has been limited in practice, but said he could participate in one-on-one drills during the second half of this mini-camp.
"It's not really until you come back that you really know where your leg is at," Rivera said. "Just holding my body up and cutting left and right, and stopping, it felt pretty good, pretty strong."