But he earned a September callup because of a 1.51 ERA in his last 30 relief appearances at Triple-A and has continued to pitch well with the Rangers. He retired the only two batters he faced in a 2-1 win on Thursday night and has a 1.80 ERA in 11 appearances with opponents hitting .235 off him.
"I've got some confidence back," Kirkman said. "I changed my arm angle and had some success at Triple-A and kept going. I kept making adjustments, and here we are."
Kirkman said he has gone back to the three-quarters angle he used in 2010, when he was a top prospect and a member of the Rangers' postseason bullpen. The question is why and how he got away from that angle.
"I keep thinking the same thing," Kirkman said. "I haven't come to a conclusion, but I have thought about it a lot."
The Rangers have used Kirkman sparingly with their overloaded September bullpen. He has pitched just five innings total in his 11 appearances.
But left-handed relievers remain a valuable commodity in the game. Kirkman is one of four in the Rangers' expanded bullpen, along with Neal Cotts, Alex Claudio and Robbie Ross Jr. Cotts is a free agent, Claudio is an unproven rookie with options and Ross is probably going to be a reliever again next season after his ill-fated trial as a starter this year.
Kirkman gives them another left-handed option, although it may prove difficult to keep him on the 40-man this winter because so many players have to be added when they come off the 60-day disabled list. But left-handers floating on the outright waiver wire draw the attention of other clubs. Pedro Figueroa, another Rangers left-hander who is facing a long road back from Tommy John elbow reconstruction surgery, was claimed twice last winter.
It would seem Kirkman will find a landing place somewhere, if not with the Rangers next spring.
"I don't have a clue," Kirkman said. "I'm going to worry about the next three games, go out and have fun, enjoy the offseason and see what happens."
T.R. Sullivan is a reporter for MLB.com. Read his blog, Postcards from Elysian Fields, and follow him on Twitter @Sullivan_Ranger. This story was not subject to the approval of Major League Baseball or its clubs.