– The free-agent acquisition of righthander Ervin Santana left one spot open in the Twins starting rotation. But the surplus of candidates for the No. 5 starter spot has helped create March Madness in the bullpen competition.

The Twins-Gophers exhibition game Wednesday kicked off the battle among relievers and more should appear Thursday in the Grapefruit League opener against Boston at Hammond Stadium.

The competition most likely won’t be decided until the final week of spring training, when the final spot in the rotation is settled and the losers in that battle are sized up for possible relief roles.

“Here we go,” Twins General Manager Terry Ryan said. “Show us what you can do.”

Righthander Jared Burton (who made 68 appearances last season) and righthander Anthony Swarzak (50) were not brought back. The group of candidates bring a variety of skill sets to the race to build a bridge to closer Glen Perkins.

“You want to look for guys that get your attention, that you can build confidence in and get you outs late in ballgames to protect leads,” Twins manager Paul Molitor said. “Other than that, you obviously need a little bit more filler guys and people to absorb some innings when the starters go short. I will say that I like the fact that we have some people that are going to give us a little bit of an option as far as different looks from what we’ve had.”

Molitor said he would rely on pitchers with experience, such as righthander Casey Fien and lefthander Brian Duensing, if he needed to protect a lead now. But he’s keeping an open mind as to how the bullpen will ultimately be assembled.

Seeking heat

The most valuable quality the Twins staff has been missing is velocity. They ranked last in baseball last season in the number of pitches thrown at or above 97 miles per hour.

One. All season.

That was thrown by Lester Oliveros during a September call-up. Oliveros is back in camp, but could be a long shot to make the team unless he improves his control.

Righthander Michael Tonkin has touched 96 mph in the past and, at 6-7, can be an intimidating presence on the mound. But his location has been spotty and he has a tendency to rely too much on his fastball. That’s kept the 25-year-old from sticking in the majors.

“That is one thing I need to do in spring training,” said Tonkin, who posted a 4.74 ERA in 25 games last season. “That, along with [pitching to] both sides of the plate pretty consistently.”

Here’s where the rotation race could factor into how the bullpen is assembled. Righthander Alex Meyer, whose fastball has reached the upper 90s, could emerge as a bullpen option if he loses the battle to enter the rotation.

Molitor said the plan is to look at Meyer as a starter for now, knowing he has little experience getting warmed up in a hurry, but those plans could change.

“I don’t know if he’s got the resiliency to pitch back-to-back-to-back, as he has never done that,” Ryan added, “but I think we’re open to it. If he doesn’t make the rotation, we have to give some consideration if he is suited to keep as a reliever. Can he help us win baseball game as a reliever?”

The same goes for righthander Mike Pelfrey but, like Meyer, he has limited experience as a reliever.

“I won’t have a choice if they come in and make that decision,” Pelfrey said. “I can’t blame anybody but myself.”

Spots up for grabs

Closer Glen Perkins, Fien and Duensing should be locks to be in the bullpen. That leaves four spots to fill in — with a pencil at this point.

Righthander Ryan Pressly and lefthander Caleb Thielbar have been around for a couple of years but will have to fight for their sports. Free-agent righthander Tim Stauffer will be given a chance to start in camp but will likely settle into the bullpen, where he has been steady in the majors.

Righthander Blaine Boyer was signed as a minor league free agent from the Padres. He doesn’t throw hard but was tough on righthanded hitters last season. Righthander J.R. Graham is a Rule 5 pick and has to remain on the big-league roster all season or be offered back to Atlanta. He’s battled shoulder problems, but Twins scouts have seen him hit 96 mph on the radar gun. Righthander Stephen Pryor, obtained from Seattle in exchange for Kendrys Morales last season, could emerge as a dark horse if he continues to inch his fastball into the mid 90s after tearing a back muscle in 2013.

Then there are the candidates, such as lefthander Aaron Thompson and righthanders Mark Hamburger and A.J. Achter, who would have to have knockout camps to make the team.

Who will work their way into a late-inning role? Who will be the innings-eater or the specialist? Who will close games if something happens to Perkins?

There are more unanswered questions about this bullpen than in recent years, questions that will be answered over the next month as the Twins sort through all the candidates.

“We all know what’s going on here and we are trying to turn the corners on a lot of avenues,” pitching coach Neil Allen said. “We’re going to put the pieces to the puzzle together the best we can.”