The Tigers, meanwhile, move on with their bullpen picture short one lefty, and a once-promising one at that.
Despite shoulder issues that essentially ended his season in mid-April, Schlereth is expected to be pitching again this spring. He'll just be doing it somewhere other than Tigers camp.
"It's just a situation where today you have to make final decisions," team president/general manager Dave Dombrowski told MLB.com on Friday. "We just felt at this time the roster space was more appealing to us than having that spot tied up with his tender."
The decision caught Schlereth by surprise.
"I just never thought this would happen," Schlereth told MLB.com in a phone interview on Friday afternoon. "This blindsided me."
Considering where Schlereth stood a year ago, a potentially big part of Detroit's bullpen, Friday's move was unexpected. But considering how his 2012 season ended, the possibility became more likely.
Schlereth came into camp last spring with the chance to play a big role in Detroit's bullpen, possibly as the Tigers' primary lefty with Phil Coke coming off an up-and-down 2011 season. Schlereth was working on consistency with his pitches, particularly a fastball that used to hit the mid-90s.
Schlereth held left-handed hitters to a .174 batting average in 2011, including 27 strikeouts in 100 plate appearances.
An early-season shoulder injury soon threw out all the plans soon enough, though it wasn't disclosed until after his early-season struggles.
The Tigers optioned Schlereth to Triple-A Toledo on April 21 after he gave up eight earned runs on 14 hits over seven innings. Soon after, he complained of shoulder trouble. After an examination revealed tendinitis, the Tigers placed Schlereth on the 15-day disabled list instead, voiding the option.
Schlereth was pitching with a sore shoulder in April, but didn't tell team officials until after he was disabled. For that, he blames himself. He said some mechanical tweaks he made over the previous year might have led to his injury.
"At the end of the day, it's my career, my doing," Schlereth said. "They did all they could do. They recognized I was hurt in the big leagues and it didn't happen in the Minor Leagues. And I'm actually thankful they did that, because being on the DL in the Minor Leagues would be brutal. I'm really thankful they did that. But there's really nothing that could've changed. It was probably bound to happen."
He never made it back to Detroit, though he did manage to avoid surgery. After spending the summer rehabbing his shoulder in Colorado, Schlereth made it back for a late August rehab assignment in Toledo. He struggled in three outings for the Mud Hens, giving up two runs on three hits with four walks and four strikeouts.
Schlereth noted at the time that the velocity on his fastball was down, and he needed to work to get it back to his earlier speeds.
"Going back to 2011, my velocity wasn't what it has been in the past, but I was effective because I was learning how to be successful at this level," Schlereth said. "I wasn't 94 or 95 [mph], where I used to be, but it was still 92-93, and I was effective."
Schlereth wasn't activated once rosters expanded in September. Still, Dombrowski said Schlereth's health wasn't a factor in the move.
"I think he was fine at the end of the year," Dombrowski said.
His recent health, however, likely played a factor in Friday's move.
"The thing that did me in probably was being hurt the entire year. That's my thinking," Schlereth said. "I didn't have bad numbers [long-term]. If you look at it, I had pretty good numbers, but they wanted to go in a different direction."
Schlereth leaves Detroit with a 3.98 ERA and a 4-2 record in 73 appearances over three seasons. He was the D-backs' first-round Draft pick in 2008, coming from the same University of Arizona bullpen that produced former Tiger Ryan Perry.
As surprised as he is about the move, Schlereth expressed no hard feelings toward the organization. He'll move on, and he expects they will, too.
"I love the team. It's a great organization," Schlereth said." Its' going to hurt a little bit, but that's life. They want to move on and I really can't do anything about that. I just have to go out and prove myself somewhere else."
Dombrowski said the move doesn't lead the Tigers into a search for another lefty reliever. Duane Below, Darin Downs, Matt Hoffman and Andy Oliver are currently on the roster with a chance to take the second lefty job in the bullpen. Casey Crosby also could end up being a factor, though he's expected to work as a starter in camp.
With right-handers Al Alburquerque and Brayan Villarreal notably effective against left-handed hitters, it's also possible the Tigers go with only one lefty in their bullpen.