FORT MYERS, FLA. – The Twins aren't ready to make an official announcement, but it's virtually certain they will enter the regular season with a rotation that consists of righthanders Ricky Nolasco, Kevin Correia, Phil Hughes, Mike Pelfrey and Kyle Gibson. Their task is a simple one: They must raise the bar from recent years in which the starters' ERA has ranked 30th last season, 29th in 2012 and 26th in 2011.

Gibson has emerged from a crowded field to earn the No. 5 spot, giving up four earned runs on 10 hits and three walks over 13â…“ innings. At age 26, it's time for the former first-round draft pick to step up and show he can be a winning major league starter.

Righthanders Samuel Deduno and Vance Worley and lefthander Scott Diamond each reported to camp with a legitimate chance to win a spot in the rotation. Deduno posted a 2.19 ERA this spring and should open the season in the bullpen. Worley, who has a 13.50 ERA, cleared waivers Friday and was sent to Class AAA Rochester. Diamond, with a 5.79 ERA, looks destined for Class AAA Rochester — if he clears waivers — but will get another chance to impress the Twins staff Tuesday against Baltimore, a game in which Gibson is the scheduled starter.

Injuries could change their plans. And the Twins could still deal a pitcher if they can get a proven hitter in return. Otherwise, the Twins will send Nolasco, Correia, Hughes, Pelfrey and Gibson to the mound. As for all five being righthanders, the Twins have made it clear since the opening of camp they were going with their five best starters.

The Twins committed $73 million in signing Nolasco and Hughes as free agents in hopes of building rotation depth by pushing down from the top. Nolasco, who was rocked for seven runs over three innings on Friday by the Mets, will start Opening in Chicago against the White Sox. Hughes is coming off a 4-14 season with the Yankees but has a 1.04 ERA this spring.

Gibson was 2-4 with a 5.63 ERA in ten starts last year and looked overwhelmed. After giving up just one run over 4â…“ innings on Wednesday in Jupiter against the Cardinals, St. Louis players commented to Twins players that Gibson's stuff was alive and nasty.

Pelfrey

Deduno pitched well this spring but could be a good fit for the bullpen since he has he had shoulder problems in each of the past two seasons and hasn't thrown more than 130 innings in a season since 2009.

The remodeled rotation is challenged to raise standards after last year's group frequently had the team battling early-inning deficits. Look at it this way: Worley, Andrew Albers, Cole DeVries, Liam Hendriks and Pedro Hernandez made 42 starts between them, going 7-18 with a 6.50 ERA. Diamond alone was 6-13 with a 5.13 ERA.

The Twins are confident they can beat those ugly numbers because Nolasco is a proven starter, Hughes won't be the pitcher he was last year, and that Gibson will take a sizable step forward in his development. If anyone is injured or struggles, they can turn to Deduno, who might have been their most effective starter last season, when he went 8-8 with a 3.83 ERA.

And hard-throwing righthander Alex Meyer, who will start the season at Rochester, could be ready by midseason. There's more talent to throw at this problem this season.

While one mystery is solved, another is getting intriguing.

The bullpen was the strongest unit of the team last season, with closer Glen Perkins, lefthanders Brian Duensing and Caleb Thielbar and righthanders Jared Burton, Ryan Pressly, Casey Fien and Anthony Swarzak.

Deduno could allow Swarzak, last season's long reliever, to move to later innings. Righthander Michael Tonkin and his 96-mile-per-hour fastball could still replace someone, too. The final games of camp will be interesting, even if we pretty much know who will be in the starting rotation.

La Velle E. Neal III • lneal@startribune.com