Mar 17, 2010 6:33 AM EST

Red Sox prospect Ryan Westmoreland underwent brain surgery Tuesday that was successful, according to a statement from the team.

A complete prognosis will not be known for a few days, a team source said, adding that the surgery "went well" for the 19-year-old, who had a cavernous malformation, or angioma, removed from his brain stem.

"Due to the complexity of this surgery, Ryan will face a difficult period initially before beginning his recovery," said the statement.

Via ESPN