For now, the 24-year-old Harvey and the Mets hope that he will be able to avoid reconstruction surgery on the ulnar collateral ligament. A full prognosis will not be made until swelling in the elbow goes down in about two weeks.
"It was tough. Obviously, it was the last thing I was expecting when I went this morning," Harvey said Monday. "I am going to do everything I can to avoid surgery."
The National League's All-Star game starter on his home field in July, Harvey has been experiencing forearm tenderness for some time, but he could not pinpoint when it began. The discomfort increased during his start Saturday against the Detroit Tigers, when he gave up a career-high 13 hits.
Harvey said he was tired against the Tigers, the 26th start of his first full season in the major leagues, and Manager Terry Collins said he noticed Harvey's pitches weren't as crisp, a sign of fatigue.
But Collins didn't know Harvey had any issues with his forearm until Sunday, and the pitcher went for an MRI exam Monday.
"Nothing is shooting in my elbow at all. That's not the issue," Harvey said. "When I heard the news, I was pretty shocked. I'm still very optimistic."
Harvey wasn't the only one in the Mets organization stunned by the news.
"This was a surprise to all of us," General Manager Sandy Alderson said. "Forearm pain can foretell problems with the elbow, but in this particular circumstance there had been no indications of that."
The seventh pick overall of the 2010 draft, Harvey is 9-5 with a 2.27 earned-run average. He has a league-leading 191 strikeouts in 1781/3 innings and was a top candidate for the NL Cy Young Award.
Outfielder Josh Reddick was put on the 15-day disabled list by the Oakland Athletics because of a sprained right wrist.
Reddick injured the wrist Sunday. He is hitting .213 with 10 home runs and 46 runs batted in.
The Athletics also designated right-hander Pat Neshek for assignment. He was 2-1 with a 3.58 ERA in 41 games.
The Philadelphia Phillies put outfielder Casper Wells on the disabled list because of vision problems two days after he took the loss as an emergency pitcher in an 18-inning game.
Wells, 28, has been part of five organizations this year. He was 0 for 7 and gave up five runs when he pitched in the 18th inning against the Arizona Diamondbacks on Saturday.
Wells is batting .128 with one RBI in 94 at-bats.