A day after his 36th birthday, Roy Halladay will undergo arthroscopic surgery on his right shoulder.

The Phillies announced the news before last night's game against the Diamondbacks. Halladay had been mulling his options but decided to have the procedure done in Los Angeles on Wednesday by Neal ElAttrache, the doctor who examined him earlier this week.

"I liked him, I thought he was spot-on," Halladay said on Wednesday in San Francisco, when he announced that he would need surgery. "I had seen him before I did the MRIs. He pretty much told me before I even went in the MRI what he thought. And when the MRI came back, it was almost spot-on with what he said. I really liked him and I was very confident with him."

Halladay and the Phillies should have a better estimate on his recovery time after the procedure. It's possible that they will see more damage in the rotator cuff and labrum during the scope.

But Halladay said ElAttrache was confident that wouldn't be the case.

"I thought it was very clear on the X-ray and he didn't indicate that to me," Halladay said. "And at no point in our conversation did he say, 'But it could be a lot worse.' He didn't say that. You can't ever rule that out, but it was never in our conversation . . . He felt like it was something that we could take care of."