The bullpen may end up being the bigger concern. Neftali Feliz has left the Rangers with doubts about his readiness to move back into the closer's role and it is growing more obvious that Soria will be asked to do that job when the season begins.
Both Soria and Feliz had Tommy John surgery in 2012. But Soria, a two-time All-Star closer with the Royals, is further along than Feliz and has had the far better spring. He has pitched seven scoreless innings over seven outings, allowing just three hits, no walks and striking out five.
Feliz had a rough afternoon against the Brewers on Friday, giving up one run in the seventh on a double by Mark Reynolds and a single by Jeff Bianchi. His velocity was down over his previous outings and his secondary stuff was inconsistent.
"I felt good," Feliz said. "My fastball wasn't good today, but I tried to keep the ball down and used my other pitches."
When asked for his assessment of Feliz's performance, manager Ron Washington pondered the question at length and then said, "He came in and got three outs."
It sounded like the manager wasn't happy with what he saw.
"I wasn't displeased," Washington said. "He got his outs. I didn't like that he gave up a run before he got the outs but he did."
Feliz took over after Scheppers went six innings against the Brewers, allowing two runs on five hits. He did not walk a batter and struck out six over 75 pitches. He has a 3.07 ERA for the spring. Opponents are hitting .208 off him and he has a 1.02 WHIP.
"He did a great job today," Washington said. "He showed me some stamina. We knew he could throw but he showed me some stamina. He had a consistent fastball and did a good job with his other stuff."
If the Rangers put Scheppers into the rotation, that would leave them with Feliz and Jason Frasor as the primary setup relievers behind Soria. Shawn Tolleson has made an impression of late and the Rangers could always move Alexi Ogando back to the bullpen.
"I feel like I've shown them I can do it," Scheppers said. "I can pitch deep in the game, that's the most important thing. At the end of the day, it's not my decision."
Ogando is the other mystery. He came to camp appearing to have a lock on one of the spots in the rotation but that seems to have changed. Ogando has a 6.35 ERA, opponents are hitting .377 off him and he has a 2.12 WHIP. There are also concerns about him being physically capable of holding up for a full season as a starter.
But Ogando, scheduled to pitch Monday, also has a proven track record of being a good Major League pitcher when he is healthy and the Rangers may fall back on that rather than react to Spring Training numbers.
If Ogando stays in the rotation with Yu Darvish and Martin Perez, it leaves two spots open. Veteran left-hander Joe Saunders remains a strong candidate because the Rangers know he can at least give them innings. Right-hander Tommy Hanson is another veteran starter who eats innings when healthy and has pitched well this spring.
Colby Lewis is another mystery. His pitch count isn't as high as the Rangers want it to be but he is pitching well and his stuff is returning to pre-surgery form. With two more starts in Spring Training or a simulated game, Lewis could be ready to return to the Major League rotation for the first time since July 18, 2012.
Ross has pitched as well as Scheppers. But if he goes to the rotation, it could leave the Rangers with Neal Cotts as the only left-handed reliever in the bullpen although Aaron Poreda, Ryan Feierabend, Pedro Figueroa and Rafael Perez are still in camp. Poreda pitched two scoreless innings against the Brewers on Friday and has a 2.45 ERA.
The Rangers promised Scheppers and Ross a chance to be starters this spring. Now they have to decide if the bullpen can survive the loss of one or both.
"They've done everything they needed to do," Washington said. "We've got a decision to make. We haven't made it."
The only thing coming clear is Soria right now being the Rangers best option at the end of the game.
T.R. Sullivan is a reporter for MLB.com Read his blog, Postcards from Elysian Fields and follow him on Twitter @Sullivan_Ranger. This story was not subject to the approval of Major League Baseball or its clubs.