Kirkman, who is unsure when the radiation treatment will begin, will be away from the team to give himself a mental break, but is hoping to continue baseball activities during the process and be back with the Rangers in a couple weeks, he said.
Kirkman thinks he may be better prepared for the challenge after going through it last year while with Triple-A Round Rock.
"I probably see it as less of a thing as it is. Other people see it as more than what it is," he said. "It's just kind of one of those things. It's kind of a blessing in disguise. I can take a step back, take a mental break and work some bugs out."
Rangers assistant general manager Thad Levine said Kirkman has had some trouble pitching with the diagnosis in the back of his mind and the team was willing to take all measures to help the 26-year-old.
As was the case last season, Kirkman will undergo intravenous therapy in addition to the radiation.
"He reached out to us and asked if he could take some time down," Levine said. "He has had difficulty succeeding."
With Kirkman on the DL, the Rangers purchased the contract of right-hander Kyle McClellan from Round Rock. To clear a spot on the 40-man roster, Texas transferred Joakim Soria to 60-day DL.
Levine said Soria threw a 35-pitch bullpen session Saturday in Arizona without reporting any setbacks and will throw another one Tuesday before graduating to throwing live batting practice.
Chris Toman is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.