ANAHEIM, CALIF. - Kyle Gibson, the Twins' top pitching prospect, has an elbow injury that could require Tommy John ligament replacement surgery.
Gibson, 23, was placed on the disabled list Tuesday at Class AAA Rochester because of a strained flexor muscle. He had an MRI exam and is heading to Minnesota to be examined by Twins doctors on Monday.
"You're always concerned it might be his ulnar nerve," Twins minor league director Jim Rantz said. "I think we've got to wait for a reading from our doctors. There's enough concern that we're bringing him to Minnesota."
Though Rantz mentioned the ulnar nerve, the team also is concerned it might be the ulnar collateral ligament, the one commonly replaced now for pitchers through the Tommy John procedure. Francisco Liriano, Joe Nathan, Carl Pavano and Brian Duensing are among the Twins pitchers who've had Tommy John surgery.
The Twins chose Gibson out of the University of Missouri with their first-round pick (No. 22 overall) in 2009. He was considered a top-10 talent but fell to them because of a fracture in his right forearm.
The Twins narrowly beat the deadline to sign Gibson that summer, giving him a $1.85 million bonus. He rocketed through their system last year, climbing from Class A Fort Myers to Rochester as he went a combined 11-6 with a 2.96 ERA.
Over the winter, Baseball America ranked Gibson as the game's 61st-best prospect. The 6-6 righthander impressed manager Ron Gardenhire and pitching coach Rick Anderson during spring training, and Gardenhire has hinted several times that he wouldn't mind having Gibson on his major league staff.
But Gibson's performance began to suffer in late May. He went 16 days between his starts on June 30 and July 17. In his last eight games, he is 0-5 with a 6.47 ERA.
Gibson could not be reached for comment Wednesday. His agent, Randy Rowley, said they could know more Thursday if one of the Twins doctors is able to read the MRI exam.
"After what he's been through, you just hope for the best," Rowley said.