"I'm glad for him so he'll be more comfortable and have better quality of life," Rangers general manager Jon Daniels said. "From a competitive standpoint, you hate to lose somebody like that, but it's the right thing to do."
Daniels said the club has known since mid-December that Diekman might need surgery. The GM said that's why they have backed away when other clubs have inquired about their extra relievers. The Rangers agreed to a one-year, $2.55 million contract with Diekman for this season last week.
The Rangers still have three left-handed relievers on the 40-man roster in Alex Claudio, Dario Alvarez and Andrew Faulkner. Claudio is the leading candidate to be the primary left-handed setup reliever even though his 85-mph fastball is the slowest on the team.
Claudio, used mostly in long and middle relief, was 4-1 with a 2.79 ERA in 39 games for the Rangers last season. He had a 1.26 WHIP and 34 strikeouts in 51 2/3 innings.
"Alex had a tremendous year," Daniels said. "We're not looking here in January at what our bullpen is, but he is in a great spot and goes into camp with the benefit of the doubt."
Claudio is planning to pitch for Puerto Rico in the World Baseball Classic. He is one of two relievers who will be away from the Rangers in Spring Training for the Classic.
Daniels said closer Sam Dyson has been asked and accepted an invitation to pitch for Team USA.
T.R. Sullivan has covered the Rangers since 1989, and for MLB.com since 2006. Follow him on Twitter @Sullivan_Ranger and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.