CLEARWATER, Fla. -- Brad Lidge took an important step forward Monday morning at the Carpenter Complex.

The Phillies' closer threw 20 pitches off a mound -- all of them fastballs -- and said afterward he felt fine. It was the first time he threw off a mound following offseason elbow and knee surgeries.

Lidge said last Wednesday that he considered himself two weeks behind schedule. He said Monday he is "a little bit" ahead of his original schedule.

"It remains to be seen how quickly I can build my arm strength," Lidge said. "As far as the pain I was having in both areas, I'm not experiencing anything yet."

But Lidge also said he doesn't feel any more optimistic about being ready to pitching Opening Day, although he said it remains a possibility.

"I didn't come out and all of a sudden feel 100 percent," Lidge said. "That being said, nothing hurts. I was able to use my body in the way that I was hoping to be able to use it this year without any pain or side effects. It's all about building arm strength now. I'm going to need to do a lot of work to get that. We'll be working hard to get that."

Phillies pitching coach Rich Dubee said Lidge could throw again Thursday.

"As long as he continues to progress upwardly each day, we're looking real good," Dubee said. "We're trying to avoid that big sharp downfall where he goes too fast and now has some type of setback. We don't want him to start tacking on too fast."

Left-hander J.C. Romero also is recovering from offseason elbow surgery. Dubee said Romero will throw off a mound Saturday.