But it came very fast, as Klein moved to Bowie after just seven games with the Keys and was in the Eastern League on May 2.
"I really didn't think about it (moving up) too much going into the year. I just wanted to throw the ball the best I could and what happens happens. They moved me pretty fast, but I wasn't thinking about it," said the 22-year-old Klein.
Klein has pitched well for both teams. He was 0-1 with an ERA of 1.15 in seven games at Frederick and is 1-0 with an 0.79 ERA in six games out of the Bowie bullpen.
"I've done a real good job of throwing everything for strikes. That's the key, pounding the strike zone, throwing what I want in certain counts. That is what's led to my success thus far," he said.
Between the two teams, Klein has pitched 27 innings, allowing 20 hits and four runs (three earned) along with five walks and 30 strikeouts. His batting average against is .202 and he has given up just two hits over 29 at-bats (for a .069 average) when pitching with runners in scoring position.
Klein's fast start has some wondering if last year's third-round pick will move to Triple-A later this summer or even have a chance to make it to Baltimore. Klein knows some players move faster when pitching out of the bullpen.
"Definitely. People always say the bullpen can be a fast track to the big leagues. But I am comfortable with what I am doing now," he said. "I know they are taking it a little slow with me and I'm on a regimented schedule. I just want to throw well. Their plan for me is their plan.
"Double-A is a phone call away from the big leagues. It is nice to be here early and doing well. It's a good place to be."
A third-round pick out of UCLA last June, Klein pitched 52 innings in college last year and the Orioles seem to be figuring on him pitching between 80 and 100 innings this season. He is working two or three inning stints every three or four days.
Does Klein expect to be a starting pitcher at some point down the road?
"It is hard to say. I see starting sometime in my future. But I will be in the pen for this year with a similar role to what I've been doing so far. But it's hard to change when you are having success in a role," Klein said.
"We'll sit down with John (Stockstill) and other people after this year and we'll go from there to plan out next year and years to come."
He said he has been able to use all four of his pitches in relief. He has a low-90s fastball, along with a curve, change and knuckle-curve.
If it turns out that Klein is asked to make the jump to Baltimore and get big league time later this year, he is confident he could make that leap.
"Yeah, if they needed me, I'd be ready," he said. "I have a lot of confidence in myself and my stuff. You have to go out there with confidence. I definitely think I could help out."
Note: The Orioles today moved second baseman LJ Hoes from Frederick to Double-A Bowie. He was batting .241 in 41 games with the Keys with seven doubles, three homers and 17 RBIs.