"I'm not sure," said Kirkman on how the decision was made. "Pitching coach Mike [Maddux] said I'd be facing lefties when I got here. That's what I'll be doing, I guess."
Kirkman was the losing pitcher in Texas' 2-1 loss. He entered in the eighth and faced four batters, three of them left-handed. Mike Moustakas slugged a leadoff double, Jarrod Dyson reached on a fielder's choice, Omar Infante flew out to right, then Kirkman hit Alex Gordon. Salvador Perez clubbed the game-winning single off Jon Edwards.
The left-hander features his lowest arm slot since 2010, when he completed his most impressive Major League stint with Texas (14 games, 1.65 ERA).
Kirkman last appeared for Texas in 2013. He posted a 8.18 ERA in 25 relief appearances and he delivered the ball from a more traditional arm slot.
"For whatever reason, I was getting higher and higher. I couldn't tell you why," said Kirkman, who hopes to add deception to his pitches with the new delivery. "I had to completely start over … eventually I got it to stick in my head, and I got it to work."
The Rangers sent Kirkman to Triple-A Round Rock for the start of the 2014 season. He started four games there, but it went poorly, as Kirkman allowed 18 runs in 10 1/3 innings.
He rebounded once restored to the bullpen, sporting a 2.45 ERA in 44 innings as a reliever at Triple-A this season.
"I'm just happy to be here," Kirkman said. "I never knew I'd make it back after the first couple months of the season."
Jackson Alexander is an associate reporter for MLB.com.