ANAHEIM -- Triple-A Round Rock pitcher Michael Kirkman continues to undergo treatment for skin cancer, but it doesn't seem to impact his pitching.
Kirkman went 4-0 with a 3.48 ERA in six starts for Round Rock during May. Opponents hit .198 off him while he struck out 9.58 batters per nine innings. The down side was he walked 19 batters in 31 innings.
"To me his consistency is starting to widen," said Danny Clark, the Rangers' Minor League pitching coordinator. "He'll have three good innings and then a bad inning. It's not inning to inning anymore."
The Rangers have been encouraged by Kirkman's progress at Round Rock. They are still frustrated by Martin Perez and Neil Ramirez, their top two pitching prospects
"They're struggling, no consistency," Clark said.
Perez has a 9.20 ERA in his last four starts, although he did allow just one run over 5 2/3 innings in his last outing against Memphis on Wednesday.
"It was one of his best starts," Clark said. "He didn't come out of his delivery except for maybe six pitches. We focused early on commanding his fastball and 20 of his first 24 were strikes. That was our goal because his issue is he gets behind hitters early in the first few innings."
Ramirez is 3-3 with a 9.79 ERA in his last six starts. He allowed eight runs in 2 1/3 innings in his last start against Memphis on Tuesday.
"Same as Martin, he can't stop one bad inning," Clark said. "Instead it keeps accumulating. That's the issue, they need to slow the game down. They want to go harder instead of slowing down and making quality pitches. Instead they want to blow people away."