Shortstop Pedro Florimon entered Thursday's game batting just .083 in August, having collected only two singles in 24 at-bats. "He's going to have to hit his way through these things," manager Ron Gardenhire said, because of the trade of Jamey Carroll to Kansas City.

That deal left Doug Bernier as the Twins' only utility infielder, so "you hesitate to make moves and use your last infielder," Gardenhire said. "We don't have too many guys who can go in there" in the event of an injury.

Florimon's slump, Gardenhire said, is because "he gets caught [with his] front foot in the air, and then he ends up rushing his swing. It's a timing thing. Whether it's not recognizing a pitch quick enough or looking for something else and then chasing, he's definitely been letting the ball get too deep on him."

It hasn't affected the shortstop's defense, however, so Gardenhire said he plans to keep playing Florimon.

Doumit back soon

Ryan Doumit's return to the Twins' roster was delayed but probably only by a day. The Twins wanted him to catch a bullpen session or two, just to make sure his "in-a-fog" symptoms have cleared and he no longer shows any other signs of a concussion.

Wednesday's game started at noon, however, so no pitchers threw in the pen before the game. Doumit caught in the bullpen on Thursday and reported no recurrence of symptoms. They got so bad during the Twins' game in Kansas City last Wednesday, he left the game after three innings and was put on the concussion disabled list.

"I feel great," Doumit said after Thursday's workout. "I'm ready to go."

The Twins were also waiting for Major League Baseball to formally clear Doumit to return, after he underwent a test given to concussion patients.

More at-bats needed

Darin Mastroianni lined a single to left in the third inning of Rochester's 4-2 victory on Thursday, a hit notable mostly because it was his first with the Red Wings. The outfielder was hitless in his first 15 at-bats in Class AAA, convincing the Twins that while his broken left foot may be healthy again, his batting stroke was not.

Mastroianni's 20-day rehabilitation assignment expired Thursday, so he was activated from the 60-disabled list, restored to the 40-man roster and optioned to Rochester, the Twins announced.

"His health is fine. Now it's just a matter of getting more at-bats [against better] competition," General Manager Terry Ryan said. "He's been in the [rookie level] Gulf Coast League, he's been at A-ball, he just could use some at-bats."

Etc.

• Nick Blackburn's 2013 season, already ruined in January when he needed wrist surgery that kept him out until July, has abruptly ended after 15 innings of Class AA and AAA pitching. The righthander's Twins career may be over, too. Blackburn will undergo surgery on his left knee on Thursday to repair the meniscus, a procedure that will sideline him for several weeks.

Blackburn's four-year, $14 million contract, which made him the third-highest-paid Twin this season (along with Kevin Correia) at $4.5 million, expires in October.

• Aaron Hicks has been placed on the seven-day disabled list at Rochester, Ryan said, because of a sore heel. Hicks, batting .227 in six games since being demoted Aug. 1, hasn't played since Saturday.