Jose Berrios admitted on Saturday that he's frustrated over recent outings and is trying to fix some mechanical issues so he can contribute to a team that's chasing an AL Central title.

Berrios left the park moments after the Twins' 9-6 loss to the Tigers on Friday, before the clubhouse was open to reporters. The club viewed that as unacceptable, met with Berrios on Saturday and now will move forward. The righthander apologized to reporters before Saturday's game and was set to resume efforts to rediscover the form that made him an All-Star earlier in the season.

"Like you guys know I'm a competitor and we are battling to win the division," he said. "I felt last night that I'm not doing my job."

Video (01:02) Jose Berrios met with the club on Saturday after not speaking to reporters on Friday

Berrios has an 8.44 ERA this month, a month in which he's left several fat pitches over the middle of the plate. That was not lost on manager Rocco Baldelli.

"I think there have been some moments where he hasn't executed where he's needed to execute and we've gotten burned in those moments," Baldelli said. "That doesn't make it easy to take. That doesn't make it easy to swallow. We're still going to spend a lot of time on the objective part of what's going on and breaking down things mechanically and getting into all those questions, but I think those are finer-point discussions that Jose will have with the pitching coach, the bullpen coach.

"I think pointing to one specific thing to kind of really just to get into isn't really fair."

Berrios feels his shoulder is flying open during his delivery at times, which leads to elevated pitches like the curveball that Ronny Rodriguez hit for a game-changing grand slam on Friday.

"I throw the pitch I want to throw," Berrios said, "but leave it in the zone [where] I don't want to leave it."

Berrios doesn't appear to be concerned about a dip in velocity. His four-seam fastball is at a season low 92.74 miles per hour in August after being near 94 most of the season. His two-seam fastball is a 91.47, nearly 2 mph slower than what it was in June.

"I'm focusing on quality rather than quantity," he said.

But the Twins might feel differently. The club is not ruling out skipping Berrios in the rotation, or at least pushing him back a few days. With rosters expanding on Sept. 1, the club will be able adjust the rotation to give Berrios and other starters more days off.

Rosario still out

Baldelli didn't sound like Eddie Rosario would back any time soon.

The outfielder is battling a tight right hamstring injury suffered on Wednesday against the White Sox. There were initial hopes that Rosario would be available by Saturday.

"He's doing pretty well," Baldelli said. "This isn't like a major hamstring issue or injury. But that being said, if it's going to take six, seven, eight days to get back to where he might be ready to play, then we have to talk about what's next."

Etc.

• Righthander Ryne Harper has a 6.35 ERA over his past 21 appearances and a 7.36 ERA this month. Perhaps the league has figured him out, or maybe he's just not making his pitches. Either way, the Twins optioned the 30-year-old rookie to Class AAA Rochester and recalled righthander Cody Stashak.

• Byron Buxton on Saturday headed for Class A Cedar Rapids, where he is scheduled to be the designated hitter on Sunday, then start playing center field on Monday. The Twins hope he's able to rejoin the team on Friday in Detroit.

• The Twins have promoted righthander Edwar Colina to Class AAA Rochester. Colina began the season at Class A Fort Myers but has had a solid season, going 8-2 with a 2.23 ERA between Fort Myers and Class AA Pensacola. His fastball can reach 97 mph and he has a solid slider and an improving changeup.