In his best Triple-A outing, Kirkman (2-0) allowed one hit over eight scoreless frames in Oklahoma City's 8-0 shutout of Memphis on Sunday. He struck out six and walked four.
The left-hander struck out the side in the first inning. Amaury Cazana grounded a single to center to lead off the second and he walked Ruben Gotay before retiring Tyler Henley and Donovan Solano. Matt Pagnozzi walked to load the bases, but Shane Robinson flied out to center to end the threat.
Kirkman retired the next five in a row, then issued a base on balls to Henley. He got the next seven batters in order, issuing a walk to Gotay to start the seventh. Gotay was erased on a double play.
In the eighth, Pagnozzi reached on a throwing error by shortstop Gregorio Petit, but Kirkman set down the side in order to end his night.
It was Kirkman's longest outing of the season, he went five innings in each of his previous starts. In his first start April 10 against Albuquerque, he was tagged for four earned runs on six hits, including a home run. He struck out four and didn't issue a walk.
He allowed two runs -- one earned -- on five hits and two walks with three strikeouts to pick up the win in his next outing April 15 vs. Round Rock. And then he scattered two runs on five hits and five walks with three strikeouts in a no-decision at Nashville.
Kirkman was selected by the Rangers in the fifth round of the 2005 First-Year Player Draft.
Chad Tracy smacked a two-run homer in the fifth and Craig Gentry and Esteban German each scored twice and plated a run for Oklahoma City (12-6)