"It was pretty surreal, I'm still letting it all sink in," Klein said. "It's close to home, a lot of family and friends coming. It will be nice."
The Rangers called up Klein and designated left-hander Ryan Feierabend for assignment. Klein didn't need to wait long for his big league debut, as he was called on to pitch an inning in the Rangers' 12-2 loss to the Indians. He gave up a home run to the first batter he faced before settling down without allowing any further damage.
"He could have been a little nervous," manager Ron Washington said. "He left a pitch down the middle to Lonnie Chisenhall. Nerves ... at least he got that one out of the way."
Klein, who stands 6-foot-7, was 3-0 with a 0.52 ERA and 10 saves over 33 relief appearances with Double-A Frisco and Round Rock. A 30th-round pick in 2011 out of nearby Youngstown State, the 25-year-old has not allowed a run in his last 35 innings over 22 appearances.
"I try not to pay attention to that," Klein said. "I just try to throw consistently good pitches outing after outing, and that stuff adds up. But it's not the goal. You just try to be consistent over time. That just happens to be a byproduct of that."
Opponents are hitting .132 off Klein, and he has not allowed an extra-base hit. In a total of 51 2/3 innings, Klein had walked 20 and struck out 70. His out pitch is his slider.
"He is a fastball/slider guy who has been an extremely hard worker and never gave into the grind," Minor League pitching coordinator Danny Clark said. "Hitters have had problems picking up his fastball. He is a big body guy who hides the ball with his delivery. He has added a cutter to put in his arsenal."
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.