OAKLAND, Calif. – Trevor May knew some Twins fans were growing impatient over his promotion, was aware that many had taken to social media to promote his cause.

"I'm a pretty big Twitter guy," the righthander, one of the Twins' top five pitching prospects, said shortly after joining his new team. "... It just gets me excited. As if I needed to be more excited."

Yeah, he doesn't expect to need much to get the adrenaline flowing Saturday, when he throws his first pitch as a big-leaguer. In fact, he is trying to prepare for the nerves and emotions as best he can, because May believes that better focus on the mound is one of the keys to his improvement this year.

May, one of the Twins' top five pitching prospects, was chosen to start Saturday's game at Oakland after posting a 2.93 ERA in 17 starts at Class AAA Rochester this season.

"That's a big part of what I worked on this offseason — staying with my approach, taking it one pitch at a time and kind of being in the moment," the 25-year-old said. "That's what good pitchers do. They're able to zone in on what they're doing, and that includes [handling] all the distractions of the debut."

Still, his parents, girlfriend and best friends are en route from his hometown of Kelso, Wash., to share in a day that already feels "surreal," May said. "It's just one of those cool things that happens in your life. It only happens once, so I'm enjoying it."

He has definitely earned it this season, even being selected to the Futures Game before a calf injury sidelined him for three weeks. He's come back strong since his leg healed, posting a 2.41 ERA in four starts since then.

"He's got a pretty heavy fastball, and he's controlled his curveball and changeup pretty well," said Eric Fryer, who caught May at Rochester through a four-start stretch in May when he didn't give up an earned run. "His slider is more of a strike pitch than a strikeout pitch. It's kind of get-them-off; I like his curve and changeup better as a strikeout pitch. But he's got a pretty heavy tilt on his breaking ball."

May represented the Twins in the Arizona Fall League last October, posting a 3.21 ERA in nine outings, mostly in relief. His rise hasn't always been a smooth one; he spent two years in Class AA with the Phillies and Twins, posting ERAs above 4.50 each time. But May, who was acquired along with since-departed Vance Worley for Ben Revere, has been excellent from the start this season.

Wasn't he getting impatient about moving up? "Not at all," May said. "If anything, it just gave me more time to really hone my game. ... I think it was only beneficial, and I'm definitely happy with where I am now."

May had to watch Friday's game from the Twins clubhouse, because he wasn't due to be put on the 25-man roster until after the game, so he wasn't allowed in the dugout.

Colabello sent down

Chris Colabello, who has not been able to reproduce the consistent production he provided in April, was returned to Rochester after Friday's game to make room for May. Colabello, who piled up 27 RBI in the season's first month, batted just .222 with nine RBI in 19 games since being recalled on July 4.

The frustrating part, Colabello said, is he feels his at-bats are almost as good as early in the season, but with lesser results.

"I don't necessarily think it hasn't clicked this time. I've hit the ball hard lately," the first baseman said. "I feel like I've had a good process throughout, but the numbers don't show it."

His roster spot was basically lost, however, when the Twins decided last week to give rookie Kennys Vargas a major league opportunity.

Etc.

• Joe Vavra, who will undergo hip replacement surgery on his left hip in the next week or two, will not return to the coach's box at third base this season, manager Ron Gardenhire said, because of his limited mobility.

• Brandon Poulson, the San Francisco Academy of Art pitcher who signed with the Twins last month, made his debut for Elizabethton on Friday — two days after he was featured in a segment on "NBC Nightly News" with Brian Williams.

• First baseman Joe Mauer went 3-for-5 for Class A Cedar Rapids on Friday and played nine innings for the first time on his rehab assignment.