DETROIT -- The Trevor Rosenthal revival attempt with the Tigers is over. The team designated the former All-Star reliever for assignment Wednesday after he was pulled mid-inning in back-to-back games, including Wednesday’s 8-1 loss to White Sox at Comerica Park.

The Tigers signed the 29-year-old right-hander to a Minor League contract at the end of June following his release by the Nationals, where his command issues cost him a late-inning role. He was called up to Detroit in mid-July. Though he allowed just three hits with 12 strikeouts over nine innings, his 11 walks and a hit batter created long innings and limited his usefulness on a rebuilding team that has leaned on relievers for heavy workloads the last couple weeks.

Even so, manager Ron Gardenhire saw progress. Given the Tigers’ struggles, however, he couldn’t see it through.

“We need innings-eaters. We need length,” Gardenhire said after Wednesday’s loss. “We can't keep [going] one inning here, one inning there right now, and I think you guys see that. We're stretching people out probably as much as he possibly can. We just have to have innings right now.

“He has worked his way through. He has gotten better and better. His arm's there. He's just got to continue working on it. We think he's on the right path coming back from Tommy John [surgery], and eventually he'll get there. That's a power arm that can really throw the ball. The big thing with him is just one inning at a time, and we just have a hard time keeping it one inning at a time. We need multiple-inning guys.”

When a player's contract is designated for assignment -- often abbreviated "DFA" -- that player is immediately removed from his club's 40-man roster, and 25-man roster if he was on that as well. Within seven days of the transaction, the player must either be released or placed on irrevocable outright waivers but not traded because the July 31 Trade Deadline has passed.

Rosenthal had been on a schedule of throwing an inning every two to three days, always entering to begin an inning. The work seemed to be yielding progress; he pitched scoreless innings in five of six outings from a perfect inning July 20 through last Saturday’s hitless, walkless inning in Texas. But he gave up a single and two walks along with two wild pitches in a three-run inning Tuesday night against the White Sox, throwing just 10 of 22 pitches for strikes and retiring only one of four batters.

The Tigers brought Rosenthal back in Wednesday for the eighth inning. He induced two ground-ball outs but walked two other batters, while throwing 15 of 26 pitches for strikes. His fastball sat just under 98 mph, topping out at 100, but he induced only one swinging strike and one called strike out of 14 fastballs thrown, with White Sox batters fouling off three more.

Add Rosenthal’s Tiger numbers with his Washington tenure, and he has allowed 23 earned runs on 11 hits over 15 1/3 innings in 22 appearances, walking 26 and striking out 17.

Rosenthal continues to search for consistent command after missing all of last season recovering from Tommy John surgery. When his delivery is sound, Rosenthal can throw nasty pitches. His challenge has been to repeat it. He could throw one pitch on the corner, then throw the next to the backstop.

The Tigers were paying Rosenthal the prorated minimum Major League salary, with the Nationals paying him the remainder of the one-year, $8 million contract he signed last November. He’ll now be placed on waivers, where any team can claim him for the minimum salary. If he goes unclaimed, he can either accept a Minor League assignment or elect free agency.