– The Twins finalized their 12-man pitching staff Wednesday, one that looks to have a split personality as it heads into the regular season.

On one hand, the rotation appears to boast stability in Phil Hughes, Ervin Santana, Kyle Gibson and, if he puts 2014 behind him, Ricky Nolasco.

But things change when you peek into a bullpen with several new faces and undefined roles.

The Twins are as confident as they have been in years that their starters will give them six strong innings a night. But they have been as unsure about their bullpen as they have in years, checking around the league recently for reinforcements, according to several sources.

“We’re going to start this way and see how it goes,” General Manager Terry Ryan said. “There are people who certainly have to perform.”

The staff was finalized Wednesday when lefthander Caleb Thielbar, a Randolph, Minn., product who made 103 major league appearances over the previous two seasons, was sent to Class AAA Rochester. Thielbar had a 5.73 ERA in eight Grapefruit League outings.

The positive for the Twins at this point is that the team is not worried about the rotation. Hughes, Santana and Nolasco all have won at least 15 games and have thrown at least 200 innings in a season during their careers. Gibson and Milone have topped out at 13 victories, but the Twins like their potential. The group looks to have the potential to keep the club in most games.

The rotation set up as follows: Hughes, Santana, Nolasco, Gibson and Milone. Hughes will pitch the season opener Monday at Detroit, Gibson is scheduled to start the White Sox home opener on April 10 and Santana is to start the Twins home opener on April 13.

“I like the dependability of the starters this spring, they have all been good,” Ryan said.

The challenge will be arranging the bullpen into an effective unit.

Blaine Boyer, J.R. Graham, Tim Stauffer and Mike Pelfrey are all newcomers to the relief corps. In a perfect world, at least two of this group would be strikeout pitchers, but only Graham has that type of stuff, as he can hit 96 miles per hour on the radar gun. But he’s a Rule 5 draft pick with no major league experience who has to remain on the Twins roster all season or be offered back to the Atlanta Braves.

The Twins have a history with Rule 5 picks with pitchers such as Johan Santana and Ryan Pressly. They protected them early before giving them a role. Manager Paul Molitor foresees more experienced relievers being used later in games, but Graham gives them the best chance of striking hitters out.

“I think everyone was in agreement,” Molitor said, “that he’s not a guy we didn’t want to be part of this team.”

Past Twins bullpens have had defined roles that were tweaked when needed. A few roles are yet to be determined with this group. Molitor has told them that more than one reliever could be called upon to pitch more than one inning, adding another layer to how the pecking order will be established.

“I don’t feel the need to specifically have exact roles for people,” Molitor said. “It is nice to at least give them a foundation for how you envision things might go, but you just don’t know day-to-day. Those things take care of themselves.”

With Duensing the only lefthanded setup man, Molitor has to identify righthanders who can handle that role. He mentioned Boyer, whose sinking fastball and newfound changeup have been effective this spring, as someone who might be able to handle that responsibility. Molitor also trusts righthander Casey Fien, who again should be the primary setup man to closer Glen Perkins.

It remains to be seen if someone other than Fien emerges as another late-inning option.

“We have some different people here, there’s no question about that,” Ryan said. “For the most part, if your rotation performs, your bullpen will hold up. That’s been our problem. We’ve had them overexposed for three years.”

With his 12-man staff set, Molitor was optimistic about the skill level of his bullpen, despite its relative inexperience.

“I think everyone in general is feeling a lot better about our chances,” Molitor said, “as far as our pitching staff is concerned, compared to some of the things we had to deal with in the past.”