FORT MYERS, Fla. -- Right-hander Trevor May was considered a frontrunner for the fifth spot in the Twins' rotation, but now that he's expected to undergo season-ending Tommy John surgery after being diagnosed with a torn ulnar collateral ligament, it opens the competition for others.
Right-hander Jose Berrios, who was scheduled to pitch for Team Puerto Rico against Team Italy on Sunday night in the World Baseball Classic, is now the slight favorite for the spot. But he'll be competing against several candidates, including right-hander Tyler Duffey, veteran Ryan Vogelsong, prospect Adalberto Mejia and Rule 5 Draft pick Justin Haley.
"Nobody wants to see a guy go down like that, but we all know Trevor was in competition for that spot," Twins manager Paul Molitor said. "The guys are definitely aware of [the competition]."
Here's a look at all five candidates for the fifth spot, and their chances of being in the rotation come Opening Day:
Berrios
Being a former Top 20 prospect by MLBPipeline.com, Berrios, 22, has the stuff and the pedigree to take a big step forward this year. But he really struggled as a rookie with an 8.02 ERA amid concerns he was tipping his pitches. He's worked to refine his delivery and allowed one run in four innings before departing for the Classic. How he pitches for Team Puerto Rico against top competition will be a factor going forward. If he doesn't make the rotation, he'll head to Triple-A Rochester.
Duffey
The Twins had high hopes for Duffey after he posted a 3.10 ERA in 10 starts as a rookie in 2015, but he had a 6.43 ERA in 26 starts last year, struggling with his command while trying to add a changeup to go with his fastball-curveball combination. Duffey, who has allowed five earned runs in 6 2/3 innings this spring, could be moved to the bullpen if he doesn't make the rotation, which is something he's familiar with, as he was the closer at Rice University.

Vogelsong
Vogelsong made his first start on Sunday (three runs allowed in 2 1/3 innings), and he will be stretched out going forward this spring, Molitor said. Vogelsong, 39, was brought in at least in part for his leadership qualities, but he believes he can still get Major League hitters out. He had a 4.81 ERA in 24 appearances, 14 starts, with Pittsburgh last year, and could make the team as a long reliever if he's not in the rotation.
Mejia
Acquired from the Giants for Eduardo Nunez at last year's non-waiver Trade Deadline, Mejia -- the Twins' No. 8 prospect -- has impressed this spring, allowing one earned run over 6 2/3 innings. The big lefty posted a combined 3.00 ERA with 126 strikeouts in 132 innings between Double-A and Triple-A last year, and is considered close to being Major League ready. There's a chance he could claim the rotation's final spot, but if not, he could be the first called up from Rochester.

Haley
Haley, a Rule 5 Draft pick from Boston, has also caught Molitor's eye with his poise and stuff this spring, allowing three runs in 6 2/3 innings. He'll get his first start on Monday against the Rays. Haley had a combined 3.01 ERA between Double-A and Triple-A last year and will get an opportunity to remain a starter this spring, but he is more likely to make the team as a long reliever.