NEW YORK -- A day after a rehab start for Class A Potomac, Nationals right-hander Jason Marquis announced Wednesday that he was not pain-free and will have surgery to remove spurs and bone chips in his right elbow.

Marquis will have the surgery Friday in Cincinnati. Dr. Tim Kremchek will perform the procedure.

Once he has the surgery, Marquis is expected to be back on the mound sometime in August. Marquis said when he woke up Wednesday morning, he realized that his elbow was in pain and had locked up on him.

"We have to see where we go from here and talk it over with the team, my agent and my family -- see what the best plan is," he said. "I let my teammates down, but they are doing a great job. We have a lot of quality guys in here. Hopefully I could come back in August and contribute."

Marquis signed a two-year, $15 million deal with the Washington in the offseason. He got off to a slow start, allowing 19 earned runs in 8 1/3 innings. The Nats began to believe that something was wrong with Marquis on April 18, when he didn't record an out and allowed seven earned runs against the Brewers.

A few days later, Marquis had an MRI and it was revealed that he had bone chips and spurs in the elbow. Marquis tried to avoid surgery. He was able to play catch and have bullpen sessions without any problems.

"It was an agreement between the player and us," general manager Mike Rizzo said. "He felt that he could pitch through it. He felt these things before and has pitched through it. We wanted to do what was best for the player. It was a mutual decision to try to let him pitch through it. It didn't work, so it set us back for about three weeks."

Marquis acknowledged that he didn't feel comfortable in his rehab start for Potomac on Tuesday. He allowed three runs in 3 2/3 innings in an 8-5 loss to Winston-Salem. Marquis threw 54 pitches, 36 for strikes. His fastball was clocked at 88 mph, which concerned the team.

"It was cold; it was tough to stay loose," Marquis said. "So I thought it was -- maybe more than anything -- why the elbow was a little stiff. I tried to stay warm and do everything that I could. Now realizing what my arm feels like this morning, if it was 85 degrees and sunny, I think it would probably be the same thing."

Strasburg receives high praise from Schilling

NEW YORK -- Former Major League pitcher Curt Schilling said on ESPN's "SportsCenter" on Wednesday morning that he hasn't seen a pitcher like Nationals right-hander Stephen Strasburg, who is pitching for Triple-A Syracuse.

Schilling, who won 216 games during his career, said he believes Strasburg, 21, has a chance to be the best pitcher in baseball once he gets to the big leagues.

"Since I'm 5 years old, I've played the game, love the game," Schilling said. "I've never seen anything like this. ... Never. Nothing close. ... Not at that age, that polished. If he comes up to the big leagues -- which he will, in the next, probably, month, some period of time before the halfway point of the season -- he'll immediately, potentially be the best pitcher in the game. He's that polished.

"And I don't know him like a lot of guys that you judge from far away. I've heard nothing bad about the kid. He's got a great work ethic, he's got a pitcher's mind, because there's a lot of guys who get to the big leagues who throw 96 [mph] who never get people out. He's pitching smart, which is rare for a kid his age. He commands the baseball. At that level, that stuff to command the baseball, I've never seen anything like it."

Olsen apologizes to Riggleman

NEW YORK -- Left-hander Scott Olsen apologized to Nationals manager Jim Riggleman on Wednesday morning for showing his emotions after being taken out of the game in the sixth inning Tuesday night.

Olsen told the skipper that he didn't realize the television camera was panning on him as he was walking off the mound.

Olsen wasn't as effective as he was in his previous start Thursday, when he took a no-hitter into the eighth against the Marlins. Olsen lasted 5 1/3 innings Tuesday and gave up two runs on nine hits, striking out two and walking one.

"You get frustrated after you get taken out of every game," Olsen said. "Other than that, it was fine. It was just frustration. You always think you could [pitch] longer, whether you are at 120 pitches or you are at 80 pitches, you don't want to get pulled out of the game. But it's going to happen."