Mendez, going into Monday's game, had pitched 11 scoreless innings, allowing three hits and five walks while striking out six. Opponents were 0-for-11 with runners in scoring position.
"He's using all his pitches, he's throwing inside to right-handers, so far he has a nice back-door slider to left-handers," manager Ron Washington said. "He comes in, throws strikes and gets outs."
The Rangers acquired Mendez from the Red Sox on July 31, 2010. He was one of three players acquired in exchange for catcher Jarrod Saltalamacchia. His progress has been slowed down the past two years by elbow issues, but now he is starting to show the Rangers how good he might be.
"It means a lot. ... To be here is important," Mendez said. "But to be successful is more important."
T.R. Sullivan is a reporter for MLB.com. Read his blog, Postcards from Elysian Fields, and follow him on Twitter @Sullivan_Ranger. Grace Raynor is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.