FORT MYERS, Fla. — Aaron Hicks, the presumed frontrunner this spring for the Twins' center field job that he has lost twice before, won't be on the team's Opening Day roster. Nor will Mike Pelfrey be in the Twins' pitching rotation — and he's not happy about it.

The 25-year-old Hicks, who has batted .201 in 150 career games over the past two seasons, was optioned to Class AAA Rochester on Saturday morning, along with another outfield candidate, Eddie Rosario. The decisions mean the Twins plan to use Jordan Schafer and veteran Shane Robinson in center field, for now, alongside Torii Hunter in right field and Oswaldo Arcia in left.

Hicks, who went just 7-for-40 (.206) with no home runs this spring, was informed of the team's decision by manager Paul Molitor and general manager Terry Ryan on Saturday morning. The former first round draft pick had started each of the past two seasons in center field, but was demoted before midseason both times.

Rosario, a 23-year-old outfielder who has yet to play above Class AA, was also returned to the minor leagues. He impressed the Twins with his newfound work ethic and quick hands at the plate, but he did not draw a walk all spring and batted just .233 (10 for 43) in 17 games.

Meanwhile, lefthander Tommy Milone was informed that he will open the season in the Twins' starting rotation, after beating out four other candidates for the job this spring. Milone, 28, will likely make his 2015 debut on April 11 in Chicago.

And that decision didn't please one of the pitchers who was passed over. Pelfrey, who posted a 1.32 ERA in 13 2/3 innings this spring, was informed that he will open the season in the bullpen, a role he has never held in the major leagues. Pelfrey said he is "frustrated and a little upset" over the move. "I was told in December [it would be an] open competition," Pelfrey said. "I don't know what happened. I wasn't outpitched."

Pelfrey, now healthy again after two seasons of recovering from elbow injuries, said he would prefer a trade to a team that would use him as a starter. The 31-year-old righthander is owed $5.5 million for this year, the second season of a two-year, $11 million contract.

Trevor May, who spent the final two months of the 2013 season in the rotation, was optioned to Rochester.

Milone, who won 25 games over two seasons for the Oakland A's from 2012-13, posted a 4.50 ERA in 14 innings this spring.

Also cut Saturday as the Twins shape their final roster: Righthander Mark Hamburger, a Mounds View High graduate and former St. Paul Saint, who had impressed the coaching staff this spring.

That leaves nine relief pitchers for the seven-man bullpen, or a competition of perhaps five for the final three spots. Assuming Glen Perkins, Brian Duensing, Casey Fien and Pelfrey are assured of spots, the finalists figure to include righthanders Blaine Boyer, Tim Stauffer and Rule 5 pickup J.R. Graham, and lefthanders Aaron Thompson and Caleb Thielbar.

The Twins also have decisions pending about Kennys Vargas' status as the team's designated hitter, and the identity of the backup catcher — Josmil Pinto, Chris Herrmann or Eric Fryer.

It's also possible that the Twins could bring in a veteran player cut by another franchise for a look during the final week. On Friday, Ryan mentioned last year's April acquisition of Sam Fuld and the 2010 signing of Jason Repko on the final weekend of training camp as past examples.