"I'd prefer to take those days off and make sure I'm ready for the second half," Rivera said during an impromptu news conference after the Yankees took batting practice.
Rivera wouldn't say he was unavailable to the Yankees up until the All-Star break, saying instead, "It's up to the manager."
Joe Girardi was not available to the media after Rivera spoke.
Rivera said the problem with his left side, his oblique, is the same one that kept him out about a week in early May.
"I've been pitching and pitching and pitching," Rivera said. "It's hard to rest it and let it heal by itself."
The right knee, which Rivera said started bothering him in Los Angeles a little more than a week ago, sounded more troublesome. He said he has fluid and inflammation around the patella tendon, though the knee has not been drained and he said a stint on the disabled list hasn't been discussed.