MILWAUKEE -- A number of Brewers officials expressed well-wishes Friday for Joe Martinez, San Francisco's rookie right-hander who was struck in the head by a batted ball during Thursday's Brewers-Giants game at AT&T Park.

Martinez suffered a concussion and three small hairline skull fractures, according to a report from the Giants' medical staff that was forwarded to the Brewers. He is alert and comfortable at St. Francis Memorial Hospital in San Francisco, and will remain there for another three or four days. He is expected to make a full recovery.

Brewers general manager Doug Melvin was worried both for Martinez and for Milwaukee center fielder Mike Cameron, whose line drive struck Martinez.

"We hope that Joe Martinez will be OK," Melvin said. "You don't wish that on anybody. Your job is go to up there and hit the ball hard, but that's not the result you want.

"Obviously, Mike was bothered by it. I hope that he's fine because he's been swinging the bat well. And the other part, Joe Martinez is a young pitcher that's worked his way to the big leagues and it's very unfortunate that he may have to spend time on the disabled list now. I just hope that he gets a chance to come back and play."

Cameron addressed reporters following Thursday's game, saying that he had a "helpless feeling" while Martinez was being tended to by medical officials near the pitcher's mound.

"I hope the young man is all right," Cameron said. "I hope he gets back on the field again.

Martinez was placed on the 15-day DL and replaced on the Giants' active roster by Justin Miller, a right-hander.