PHOENIX -- Oakland A's outfield prospect Javier Herrera will miss the season after undergoing Tommy John surgery within the next week. The 20-year-old from Caracas, Venezuela, reported pain in his right arm after a recent game at the A's Minor League complex.
"We took him in, had him examined and we got the diagnosis," A's director of player development Keith Lieppman said Thursday. "It's hard to tell whether it happened in one throw or if it was a combination of other things."
According to A's assistant general manager David Forst, Herrera will visit with specialist Dr. Lewis Yocum this weekend in Los Angeles for an examination.
"It's unfortunate," Forst said of the injury.
Herrera, who will undergo a procedure which will replace ligaments in his right elbow, was in big-league camp through March 13 after playing winter ball and appearing in the Caribbean World Series. He was 2-for-10 in six games for the A's.
"I think it's good experience and great for his development," A's manager Ken Macha said the day Herrera was reassigned to the Minor League camp. "He can run, play center field and he has a cannon for an arm."
Herrera played for the A's affiliate in the Dominican Summer League after signing with the organization as a non-drafted free agent in July 2001. He's also played in the rookie league, and the past two years, he played at the Class A level.
Herrera also made a brief stint with Triple-A Sacramento last May, going 5-for-12 with a home run and three RBIs in five games.
"He has been outstanding," Lieppman said. "He's had sore arms in the past, but nothing that required treatment."
Lieppman said he was told the rehab time is eight to 10 months, which means Herrera also will likely miss winter ball, but he should be healthy by Spring Training next year.
Herrera, rated the A's second-best prospect by Baseball America
, has made huge strides the past two years. In addition to a strong arm, he can run (26 stolen bases at Class A Kane County last year) and has some power (13 home runs).
"He was in great shape, and we were looking for a breakout year from him," Lieppman said.
Rick Eymer is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.