ARLINGTON, Texas - After Friday’s game, the Twins announced the first wave of September callups.

Righthander Tyler Duffey, catcher Chris Gimenez, lefthander Andrew Vasquez, outfielder Johnny Field will join the team, from Class AAA Rochester, in time for Saturday’s game against Texas, and righthander Matt Belisle will be activated from the disabled list after recovering from right knee soreness.

Saturday is the first day major league rosters can expand to include players on the 40-man roster.

It will be Duffey’s fourth promotion to the majors this season. He has a 6.35 ERA in 11 appearances with the Twins.

Gimenez was traded to the Twins on Thursday by the Cubs in exchange for catcher Bobby Wilson.

Field was called up Aug. 6 from Rochester before being sent back down on Aug. 19. He was 1-for-16 in eight games with the Twins. Vasquez was recently promoted to Class AAA Rochester and has a nasty slider.

Belisle has a 9.15 ERA in 19 games with the Twins. He was placed on the disabled list Aug. 7 and spent recent weeks tinkering with his mechanics in order to add movement to his pitches.

“He’s been trying a little bit of a different arm slot, some of those things to give himself a better chance,” manager Paul Molitor said.

Twins General Manager Thad Levine declined to clarify Bryon Buxton's chances of being called up. The team said earlier in the week that he might not be called up, and that should not be taken lightly. Also, Levine said, Buxton is playing with some discomfort in the wrist that sent him to the DL a few weeks ago.

What about Sunday?

Kyle Gibson will start on Monday at Houston. That leaves an opening in the rotation.

“So sometime before that, probably Sunday, there will be an extra spot slotted in,” Molitor said. “So if we finalize the callups and all that, we’ll be able to make more announcements regarding the rotation at the back end in Texas in particular.”

The Twins will likely go with a six-man rotation in September. But there will be times they use an “opener” to pitch an inning or two before the starter replaces him and pitches a couple of times through the order.

That could happen as soon as Sunday.