On Monday, the pitching schedule was posted in the clubhouse at Bright House Field. It said that Cole Hamels would face hitters in a live bullpen session for the first time this spring on Thursday.

Thursday arrived, and it wasn't the persistent rain showers that cancelled the throwing session. Hamels was simply not strong enough to throw.

After throwing two bullpen sessions in his quest to join the Grapefruit League rotation in mid-March, Hamels suffered a setback on Saturday when he said his body felt fatigued after throwing off the mound.

"I believe I threw 35 pitches," Hamels said. "To my body it felt like a thousand."

Hamels won't throw off the mound again until next week at the earliest. Originally, it was asummed Hamels would be able to join the rotation after missing just a start or two in April.

That timetable has changed.

"I think I pushed it a little too hard too quickly," Hamels said. "And I wasn't able to recover the way I obviously use to or would be accustomed to. ...

"I didn't feel like it was safe to push it in that direction because I think that would have led to injuries. So I'm just really trying to allow my body to catch up. I'm trying to build the biggest base of strength that I possibly can to throw. And in the short period that I have had, I wasn't able to build it the best I could to face hitters."

Hamels wouldn't say if he thought he'd be able to throw his first pitch of the 2014 season in April.

"I think that's the last thing I'm going to think about," he said. "Ultimately I just want to get back out and get on the mound and see how I'm going to fare there."

Hamels said there is no MRI scheduled. He also will not have a cortisone shot.

"I've had all the tests done that would basically that they're required to do and everything checked out," Hamels said. "So that's the thing. And I knew nothing has gone wrong. I just think that just trying to get in the best possible shape that I can in sort of a rushed, competitive atmosphere, something's going to not want to push it a little more so it prevents the injury, so ultimately my body's telling me, 'Hey, slow it down a little bit and start over in a certain way so that you can prevent injury but build up for the long haul.'"

Hamels entered camp behind schedule after dealing with biceps tendinitis in November. But he said he was healthy when he entered camp and repeated the refrain for the next three weeks.

But suddenly that's no longer the case and there is real reason for the Phillies to be concerned.

Cliff Lee is a near-lock to start on Opening Day on March 31 in Arlington, while A.J. Burnett, Kyle Kendrick and Roberto Hernandez are likely to follow in the starting rotation. Beyond those four starters, the Phillies have little certainty.

Jonathan Pettibone has yet to pitch in a Grapefruit League game after battling a shoulder ailment in February. Ethan Martin was shut down five days ago; he isn't expected to begin throwing again for 2-3 weeks.

Cuban free agent Miguel Alfredo Gonzalez has looked rusty, fellow righthander David Buchanan has only made six starts beyond Double-A, and GM Ruben Amaro Jr. has said top prospect Jesse Biddle was not a candidate for the major league team. Non-roster players in camp include Jeff Manship and Sean O'Sullivan.

Hamels is entering the second year of a 6-year, $144 million contract. It's the richest contract in franchise history.