Twins promote reliever A.J. Achter, catcher Chris Herrmann

TORONTO – The Twins' eight-man bullpen isn't working out lately. So the Twins are going to try it with nine.

A.J. Achter was recalled from Class AAA Rochester after Thursday's 9-3 loss to the Blue Jays, swelling the Twins' relief corps to nine, at least temporarily. Achter, a righthanded reliever with a 2.82 ERA and 14 saves for the Red Wings, will meet the team in Cleveland.

Tyler Duffey, who lasted only two innings in his major league debut on Wednesday, was returned to Rochester.

The enlarged bullpen figures to last about a week, until the Twins need a fifth starter on Aug. 15. Monday's off day will allow the Twins to start Kyle Gibson on Tuesday, pushing back any decision about the rotation for nine days. Tommy Milone, on the disabled list with a mildly sprained elbow, is eligible to return Aug. 16.

Meanwhile, the Twins also exchanged backup catchers once again, recalling Chris Herrmann from Rochester and designating Eric Fryer for assignment.

This will be Achter's second stint in the majors; the Michigan State alum, a 46th-round draft choice in 2010, posted a 3.27 ERA in 11 innings as a September call-up last year. He was an International League All-Star this season, though, and has held Class AAA hitters to a .167 average.

Herrmann was demoted in early June after batting just .156 as Kurt Suzuki's backup, but Fryer fared no better. He hit .167 in seven games and struck out 10 times in his last 11 plate appearances.

"He's done everything [necessary], and I believe he'll be cleared in the very near future," assistant general manager Rob Antony said.

But Pinto might not wear catcher's gear for a while, Antony said. After such a long absence, the Twins want to keep his comeback as stress-free as possible, so the 26-year-old Venezuelan will likely be limited to a designated hitter role this season.

Pinto isn't the only Twins prospect about to beef up the Rochester lineup. Byron Buxton will report to the team in Charlotte, N.C., Friday and will serve as the designated hitter Friday night.

Buxton, the overall No. 2 pick in the 2012 draft, will return to the outfield over the weekend.

"That will begin his official 20-day rehab" from a strained left thumb, suffered while sliding into a base on June 23, Antony said. "I have not seen anything that said he's restricted."

• Brian Dozier struck out on a called third strike in the fifth inning, the 16th consecutive game with a strikeout for the All-Star second baseman. That's one short of the longest such streaks in franchise history. George Mitterwald in 1971 and Chris Colabello last season both struck out in 17 straight games.