ARLINGTON -- The Rangers don’t have any classic position battles brewing in Spring Training, but they do have position mysteries.

The Rangers go into camp with a set starting rotation and lineup. The bullpen? Well, every team has relievers battling for spots in Spring Training.

So, what are the mysteries? Here are five as Spring Training nears:

The Danny Santana mystery
Danny Santana is the leading candidate to be the Rangers' starting center fielder, and he can also handle every position but pitcher and catcher. General manager Jon Daniels and manager Chris Woodward place high value on that.

So who plays center field if Santana moves around? That could be the scenario Daniels referred to when he said the Rangers could sign more players even after Spring Training begins. Proven veteran Kevin Pillar remains unsigned.

“There are still a number of free agents out there, some of which we have interest in,” Daniels said. “A couple of guys [there's] non-roster interest, a couple of guys we are still at least discussing how they fit on the club.”

The Rangers also want to look at Nick Solak, Scott Heineman, Eli White and Leody Taveras in center. Solak and White are infielders by trade, but the Rangers want to see them in center. Heineman is an experienced Minor League outfielder who has played the corners more than center field. Taveras, 21, is a proven defensive talent in center, but he would be making the jump from Double-A.

“I really want to see some of these guys to see if they can play that position and give us a chance to move Danny around,” Woodward said. “Right now I see Danny playing out there more than anybody else. But I’d like for one of these guys to come in, tear it up and force our hand.”

The Nick Solak mystery
Solak has offensive talent, hitting .293/.393/.491 in 33 games for the Rangers last season. The Rangers need to find him a spot, and Solak understands his Major League career may begin as a utility infielder.

“I love what I saw from him last year with the bat quality,” Woodward said. “I expect him to be the guy who forces my hand and earns those at-bats.”

Second base was Solak’s primary position in the Minors, but the possibility of him pushing Rougned Odor aside is remote at best. Odor is owed $33 million over the next three seasons.

Solak has worked at third base but has limited experience both there and in center. If Solak can play either in center or at third, that would greatly increase his chances of making the Opening Day roster.

The Ronald Guzmán mystery
Ronald Guzmán is the Rangers' incumbent first baseman. That does not guarantee him a job. Woodward said Guzmán still has to make the team out of Spring Training.

The Rangers made that clear when they signed Greg Bird, a left-handed power bat, to push Guzmán.

“[Guzmán] is one of the guys who really needs to take a step forward,” Woodward said. “He does need to show more consistency in his bat quality, controlling the strike zone. I think he’ll be fine, but it’s going to be a big one coming into spring because he does have competition. It is time for him to take the next step.”

Guzmán, in his second season in the Majors, hit .219/.308/.414 last year. Against left-handers, that slash line dropped to .134/.238/.299.

That’s why the Rangers acquired first baseman/outfielder Sam Travis from the Red Sox. Over three Major League seasons, Travis hit .250/.320/.401 against lefties. In the Minors, he hit .325/.391/.528 against lefties. But Travis will be dealing with a hamstring injury at the beginning of camp.

This is also where Solak’s ability to handle third base comes into play. If Solak can handle third, the Rangers could move Todd Frazier to first base against lefties. Frazier was signed to be the Rangers' third baseman, but he has made it clear he has no problem playing at first, if needed.

The bullpen mystery
The Rangers will use an eight-man bullpen, and at least four spots are taken: closer José Leclerc; right-handers Jesse Chavez and Rafael Montero; and left-hander Joely Rodríguez, who is coming over from Japan on a two-year deal.

Right-hander Nick Goody, claimed off waivers from the Indians, and left-hander Brett Martin also appear to have inside tracks on two of the jobs. That leaves two spots open, and the candidates can be divided into two camps.

There is the young talent: right-handers Jonathan Hernández, Luke Farrell, Ian Gibaut, Joe Barlow, Demarcus Evans, and left-handers Yohander Méndez and Kyle Bird.

Then there are the non-roster candidates, led by right-handers Edinson Vólquez and Cody Allen. That group also includes left-handers James Jones and Brian Flynn, and right-handers Juan Nicasio, Luis García, Taylor Guerrieri, Derek Law, Jimmy Herget and Tim Dillard.

The Rangers were not aggressive in the free-agent relief market.

“Overall, we didn’t think that was the strength of the market this year,” Daniels said. “We thought we had some good options internally and wanted to see our young guys there, as well.”

The Jeff Mathis mystery
Jeff Mathis was the Rangers' Opening Day catcher last season, but he has been supplanted by Robinson Chirinos. The Rangers also have Jose Trevino, who handled himself well in a part-time role as a rookie last season.

Mathis, who is signed for this season at $3 million, still has defensive and leadership qualities that the Rangers value. He will also be 37 on March 31 and hit .158 this past season.

The mystery is if the Rangers will stick with Mathis or cut their losses and go with Trevino as the backup. Adding to the mystery is that the Rangers signed former Red Sox prospect Blake Swihart as a non-roster invitee and plan to give him a real shot at catching.