In his two previous outings, Kirkman had allowed 14 runs in 8 1/3 innings. He'll likely get two more outings before the end of the month. Kirkman was 0-2 with an 8.18 ERA in 25 appearances for the Rangers before going on the disabled list on June 6 to undergo treatment for skin cancer.
"He's still on the radar," Rangers manager Ron Washington said.
The other left-handed relief candidate for September is Joseph Ortiz, who is 2-1 with a 3.04 ERA in 17 games at Round Rock. He has also made 25 appearances for the Rangers with a record of 2-1 and a 3.96 ERA. Round Rock's season ends on Sept. 2 and the Express is not going to be in the Pacific Coast League playoffs.
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.