PAWTUCKET, R.I. -- Red Sox catching prospect Mark Wagner, who was splitting time with Dusty Brown in Triple-A Pawtucket, learned Friday that he had a fractured hamate bone in his left hand and will undergo surgery Tuesday in Boston. He is expected to be out six to eight weeks.
Wagner sustained the injury while taking a swing and fouling off a pitch in Thursday's 4-1 home loss to the Indianapolis Indians.
"What are you going to do, you know, one of those things,'' Wagner said. "Just found out 15 minutes ago I'm going to need surgery.''
After Tuesday's operation, Wagner will report to Fort Myers to rehabilitate at the team's minor league facility.
Wagner was placed on the seven-day disabled list and the PawSox activated Gustavo Molina, who had been on the DL with a strained right calf.
Wagner was batting .226 with two home runs and eight RBIs. He had pounded left-handed pitching (7-for-17, .412, 2 HRs) but was batting just .139 (5-for-36) against right-handers.
A ninth-round pick in 2005, Wagner, 25, is in his sixth season with the organization. Last season, while playing for Double-A Portland, he threw out 62 percent of baserunners attempting to steal (18-of-29). After being promoted to Pawtucket, he threw out 36 percent (16-of-44) of would-be basestealers. This season, he's thrown out 2-of-11.
He and Brown were the most likely candidates to be called up if the Sox needed a catcher.
"Just something I have to accept,'' Wagner said, "and work hard to get back. I told the doctor, 'Let's do it now.' Quicker, the better.''
The injury is not uncommon in baseball. Dustin Pedroia played the last two months of the 2007 season with a fractured left hamate before undergoing offseason surgery in November. Wily Mo Pena and Eric Hinske also had hamate surgery, as did David Ortiz back in 1998, when he had the bone removed from his right hand.
The hamate is a hook-shaped bone in the wrist, located at the base of the ring and pinky fingers. It owes its shape to its function, which is in part to protect a sheath of tendons, blood vessels and nerves traveling from the arm to the fingers in the hand. It is not a particularly important bone, and many players have the bone removed. Wagner expects that will be the case when he has surgery Tuesday.
No one is quite sure why the hamate breaks; it has happened to golfers who have hit the ground with a bad swing. John Manuel of Baseball America once wrote this:
"Trainers aren't sure why the hamate breaks, though some say it's because the handles of today's bats are thinner, or because batters often clutch the knob of the bat. Energy from the bat on a swing can sometimes jump to the hand like a lightning rod, and the hook of the hamate sometimes breaks under the strain.''
Gordon Edes covers the Red Sox for ESPNBoston.com. Follow him on Twitter.