Royals Top Prospect John Lamb to Undergo Tommy John Surgery

Kansas City Royals left-handed pitching prospect John Lamb will have Tommy John surgery tomorrow, according to the Royals Twitter feed. Lamb was ranked as the 41st top prospect in all of baseball by Keith Law and the 11th by Kevin Goldstein of Baseball Prospectus. He was ranked 18th by Baseball America.

Lamb was pitching for the Northwest Arkansas Naturals - the Royals' Double-A affiliate - when he left his May 19th start with elbow discomfort. According to Baseball America, he had been missing about four MPH on his fastball for a majority of this year.

Lamb is only 20 years old and should be able to come back and pitch well. However, his ETA to the big leagues has now been pushed back from early 2012 to at least early 2013.

This is a big blow to the Royals chances in the meantime, as Lamb projected to be a top starter in their rotation along with Mike Montgomery.