SAN FRANCISCO -- Red Sox catcher Victor Martinez suffered a fracture on the top of his left thumb and will be evaluated Monday in Boston.
Martinez suffered the injury in Sunday's 5-1 win at San Francisco and was replaced by Jason Varitek in the bottom of the fourth inning.
Martinez initially injured the thumb in the second inning when a foul ball off the bat of Pablo Sandoval hit off his thumb before striking his left foot. He was hit on the thumb again in the third inning on a foul ball by Andres Torres.
Martinez went out to warm up pitcher Jon Lester for the fourth inning but his thumb had swelled up so much he couldn't stay in the game. An X-ray revealed the fracture.
The Red Sox hope Martinez won't have to go on the disabled list. He was wearing a small wrap on the thumb after the game.
"It's not a given that he'll go on the DL but it's not a given that he'll be OK, either," manager Terry Francona said. "We'll get him examined tomorrow and we'll see where we go from there."
Martinez, who missed three games last month after Tampa Bay's Jason Bartlett fouled a ball off his left big toe, leaving it swollen and discolored, also was hopeful of avoiding the DL.
"I don't think I'm going to have to be on the disabled list," Martinez said. "There's pain, but we'll see how it feels tomorrow. It's a good thing we have an off day tomorrow. I'm going to have it checked out again and see what happens."
Martinez's thumb was the latest injury the banged-up Red Sox suffered in San Francisco over the weekend.
Second baseman Dustin Pedroia is on the disabled list with a nondisplaced fracture of the navicular bone in his left foot after fouling a ball off it against the Giants on Friday. The team has not set a timetable for his return.
Clay Buchholz, a 10-game winner, left his start Saturday after one inning because of a hyperextended left knee that he hurt running the bases.
"We definitely want to get out of here," Martinez said.
Gordon Edes is ESPNBoston.com's Red Sox reporter. He has covered the Red Sox for 12 years and has reported on baseball for 25 years. Ask a question for his next mailbag here. Information from The Associated Press contributed to this report.