LAKELAND, Fla. -- Brayan Villarreal says his arm is fine after cutting short his winter ball season in Venezuela as a precaution due to elbow soreness. Now that he's full-go in his throwing program, his command is his priority as he tries to sew up a spot in the bullpen.

The Tigers know what he can do when he's on, having seen his impact during the summer. They also know what he can do if his command is out of whack, which the stretch run showed before the Tigers left him off the postseason roster.

"He has shown some bigtime signs at times," manager Jim Leyland said, "and he has shown some signs of being erratic at times."

Villarreal is one of 15 "legitimate candidates" for the bullpen, by Leyland's count. That includes pitchers with relief spots wrapped up, such as Joaquin Benoit, Octavio Dotel and Phil Coke. That also is believed to include Rick Porcello and Drew Smyly, who could end up in the bullpen depending on which one of them wins the fifth starter role.

Villarreal has one of the more electric arms, but not one of the more consistent ones. He planned on working on that in winter ball, but was shut down after just three innings due to the elbow concern.

"I've just been working on my mechanics and with men on base," Villarreal said on Sunday morning. "I was going to work on that [in winter ball], but I didn't have time. That was what I had in mind."

Rule 5 pick Kobernus in outfield mix

LAKELAND, Fla. -- Jeff Kobernus spent the last few years as a second baseman in a middle-infield logjam in the Washington Nationals' farm system. He never played a game in the outfield in the Minors.

Kobernus is about to enter the Tigers' outfield mix.

He knew he had a better shot at making it to the big leagues when Detroit selected him in the Rule 5 Draft. He just didn't know where.

"It's exciting," Kobernus said.

The Tigers had Kobernus' outfield capabilities in mind when they plucked him from the Nationals' roster in December. At the time, though, they were still exploring possible outfielders on the open market who could serve as a right-handed hitting complement to Andy Dirks in left field.

The Tigers didn't sign anyone. Team president/general manager Dave Dombrowski said last week they could still swing a trade this spring, but they're going to look at what they have in camp first. Top prospects Avisail Garcia and Nick Castellanos are intriguing options, but Dombrowski has said he doesn't want to stunt their development by promoting them to the big leagues if their playing time is going to be limited.

Garcia platooned in right field down the stretch last season, but that was after the Minor League season had ended.

As a Rule 5 pick, Kobernus, the Tigers' No. 16 prospect, has to make the big leagues, or else the Tigers have to offer him back to the Nationals. Between his situation, his right-handed bat and his speed, he's going to get a good look.

"I think he's a very interesting guy," manager Jim Leyland said, "and he will definitely get every possible look, being a Rule 5 guy, to see if he's a fit or not. I have no idea at this juncture whether he is or he isn't, but I trust our scouts, and he was recommended, and we took him, and he's an interesting guy."

Kobernus has a track record of hitting left-handed pitching, batting .326 off southpaws last year at Double-A Harrisburg and .306 in 2011.

Leyland mentioned reports have also been positive about Kobernus as a second baseman. He won't see much time there, obviously, with Omar Infante entrenched. He'll still get a good share of work with the infielders this spring.

The outfield work will start with drills, possibly some extra fly balls after workouts with Tom Brookens and other coaches. How it develops after that remains to be seen.

"I worked there a fairly decent amount in the offseason and I played [there] in college," Kobernus said. "It's just kind of one of those things that, once I get back doing it, I start to feel more and more comfortable. Doing the reps, you get more comfortable and just try to improve every day."

Boesch dealing with right oblique soreness

LAKELAND, Fla. -- The gut reaction to news that Brennan Boesch tweaked his right oblique while taking batting practice on Saturday afternoon is that nobody can afford an injury less than Boesch, who's trying to work his way back into the Tigers lineup.

But the fact that the Tigers' first Spring Training game isn't until next weekend, and that Boesch dealt with minor injuries last Spring Training means that Boesch has every reason to be cautious with an injury right now.

He's as aware as anyone how important this spring is for him. He had no qualms spending Sunday getting treatment.

"It's February. I don't want to take any chances right now," Boesch said. "Get it over with so I can get plenty of at-bats in Spring Training."

Boesch said he came to camp with some tightness there, but felt it on a swing on Saturday. He characterized it as a day-to-day situation.

"I'm optimistic I'll be out there in the next day or two," Boesch said. "The most important thing is not rushing it so I get all the at-bats I need in spring to compete and to prepare for the season."