Pavano, who has been on the disabled list since June 4 with a strained right shoulder, will instead throw another live bullpen session before deciding when to make his first rehab outing.
He was expected to throw about 40 pitches in his first rehab start but Pavano is being cautious, as he doesn't want to experience a setback.
"Pavano has pushed his official rehab back," Ryan said. "He's going to throw BP here this week. He's not quite ready to pitch in a game. We're going to move him back some. He's going to throw live BP on Friday. He doesn't feel strong enough to want to go and pitch in a game."