The revolving door attached to the Twins rotation continued to spin Friday with Anthony Swarzak making a spot start against Detroit. This came one day after call-up Cole De Vries made his major league debut in Chicago.

One working theory is that the Twins promoted De Vries and not Liam Hendriks because they wanted to send a message to Hendriks that he needs to make a few necessary adjustments before he gets another opportunity with the big club. That's certainly plausible but, if anything, De Vries' audition should resonate louder and more pointedly with a guy stashed away in the bullpen, Francisco Liriano.

If this youth movement infiltrating the rotation doesn't motivate Liriano to get his act together, maybe nothing will. Banished to the bullpen after a dismal start to his season, he is trying to resurrect his game under mostly benign conditions while the Twins reshape their rotation with call-ups from Class AAA Rochester, which begs the question: What is the end game for Liriano?

"We've said all these years that we love his stuff and we hope that someday he puts it together," Twins pitching coach Rick Anderson said. "Our goal putting him in the 'pen was to try and get some confidence and throw some zeros up. You need something to build his confidence. If he ever gets it right, he could jump back in the rotation and be pretty good."

That statement is particularly telling when you consider the current state of the Twins staff. If Liriano is too flawed to pitch in this rotation, what does that say about his potential trade value? A pending free agent this winter, Liriano figured to be shopped before the trade deadline, but those probably would be brief conversations right now. The Twins need him to right himself in order to bolster the rotation and inflate his trade value. From Liriano's perspective, he needs to pitch effectively to maximize his market value.

His outing Friday did little to move that needle. Entering in the fourth inning for an ineffective Swarzak, Liriano gave up five hits and four earned runs in 2 2/3 innings in a 10-6 loss.

It was his fifth relief appearance since being demoted on May 9, and his longest of the five. In the prior four, he didn't give up a run in 4 2/3 innings.

Liriano sees progress.

"Things are getting better," he said prior to Friday's game. "I'm getting ahead in the count. That's one of the problems I've had in the past. I need to get ahead in the count with my fastball and everything else will work for me."

Liriano said he hasn't discussed his future as a starter with Anderson or manager Ron Gardenhire recently.

"I'm ready, but I'm not worrying about that right now," he said. "I'm just trying to help the team win some ballgames from the bullpen."

Except that role still doesn't make much sense. The decision to pull Liriano from the rotation was absolutely the right one. He was a mess on the mound -- 0-5 with a 9.45 ERA -- and needed to regroup emotionally. The Twins just couldn't keep sending him out there expecting different results.

But Liriano would be better served as a starter in Rochester rather than pitch an occasional inning or two in mop-up duty here. Gardenhire indicated initially that allowing Liriano to pitch in the minors might be counterproductive because hitters are not nearly as disciplined and his problems often stem from an inability to locate his fastball.

Of course, Liriano holds ultimate leverage in this discussion, as he can dictate whether he accepts a minor league assignment due to his major league service time. Why not go to Rochester, build some confidence and then return to the rotation? That seems more beneficial than holding a marginal role in the bullpen.

"We've thrown things around with him," Anderson said. "This is what he wanted to do and we'll run with it."

It's no secret that Liriano's problems tend to be more mental than physical. His stuff isn't as dominant as it once was, but he's still the team's most talented starter. But he often unravels in tough spots, his mechanics go haywire and he starts to overthrow.

"I've said many times that if you get in a controlled atmosphere in the bullpen and watch his stuff, you think, 'Oh my goodness,' " Anderson said. "When the game starts, what happens? He gets too much in a hurry. We always say you control the situation, don't let the situation control you."

Liriano is a fascinating case study that way. Maybe he will get another chance as a starter, but for now, he has fallen behind some youngsters in the pecking order. It's up to him if it stays that way.

Chip Scoggins • ascoggins@startribune.com