The Twins’ eight-man bullpen might be shrinking. Or another of their top prospects could be headed to the major leagues.

The team isn’t ready to say yet what the plans are for roster spot No. 25 on Friday, but those appear to be the likeliest scenarios. Righthanded reliever Michael Tonkin was sent back to Class AAA Rochester after the Twins’ 6-1 victory over the White Sox on Wednesday, but manager Paul Molitor wouldn’t elaborate on who will be in uniform instead on Friday.

Minnesota has carried 13 pitchers, eight of them relievers, since May 22. Molitor chafed at reducing his bench to three players and has mentioned several times in the past month that his preferred roster would have four players on the bench and seven in the bullpen. Twins starters have lasted at least six innings in eight of their past nine games, so the bullpen’s workload has been reduced. And the team is headed to Milwaukee and Cincinnati, National League cities where pinch hitters are used more frequently.

If the bullpen is reduced, it could be to recall Danny Santana, who responded to his demotion two weeks ago by collecting 20 hits in 14 games, nine of them for extra bases, and drawing four walks, giving him a .369 on-base percentage. Less likely to be promoted is Oswaldo Arcia, who is hitting .192 at Rochester with only one home run, or Josmil Pinto, who is recovering from a concussion.

Should the Twins keep 13 pitchers, however, it might mean Molitor and General Manager Terry Ryan are intrigued by Alex Meyer’s success in the Rochester bullpen. The 25-year-old former first-round pick was 2-3 with a 7.09 ERA as a starter but has reverted to his top-prospect form as a reliever, allowing just one earned run in 16⅓ innings over eight appearances, a 0.55 ERA.

“The reports are really good. He’s throwing it over, throwing it hard, using his off-speed pitches,” Molitor said on Monday. “Obviously, when we talk about people who might help us, his name is going to come up.”

Tonkin, called up just two weeks ago, appeared in four games during this stint, allowing four hits and two runs. He has a 5.73 ERA in 16 major league appearances this season.

Hicks to start rehab

Aaron Hicks is also headed to Rochester, assuming his workout Thursday goes well. He will join the Red Wings on Friday to begin a rehab assignment as he recovers from a right forearm strain.

Hicks is eligible to be activated from the disabled list Sunday, but Ryan said no decision has been made about when the outfielder will rejoin the team. Or whether he will at all.

“Let’s see what he does down there,” Ryan said. “There are no promises when we make moves. People have to earn their stay and earn their keep.”

In Hicks’ case, it may come down to a decision between him and rookie Byron Buxton, who struck out four times Wednesday and is hitting .189 in the majors.

Etc.

• Brian Dozier hit his 23rd double Wednesday, one fewer than Cleveland’s Jason Kipnis for the major league lead. It puts Dozier on pace for 52 this season, which would easily be the most in Twins history. Justin Morneau, with 47 doubles in 2008, holds the franchise record.

• Molitor on the upcoming road trip, the Twins’ last interleague road games: “You have to prepare your pitchers to hit. We had a fun day yesterday, with the entire staff out there getting some bunting in. But it will be nice to have that behind us.”