SURPRISE, Ariz. -- Veteran right-hander Edinson Vólquez threw his first bullpen session of Spring Training on Thursday. Left-hander Drew Smyly and right-hander Shelby Miller take their turns Friday.
Three pitchers who are coming back from Tommy John surgery are staying up with the others at Rangers camp in the early going.
"They are not on a rehabilitation program," assistant general manager Shiraz Rehman said. "They are on a regular program. There are no restrictions on their program.
:: Spring Training coverage presented by Camping World ::
This was Volquez's fifth bullpen session of the winter, including four in the Dominican Republic.
"It feels good," said Volquez, 35. "My arm feels really good. It was a good one. I'm excited to be here and throw the first one. Everything is going my way. "
All three are expected to throw two bullpen sessions and two live batting practices before the start of Cactus League games.
"After that we'll figure it out," pitching coach Julio Rangel said. "So far they have been great, their arms feel great. We might slow-play them early on, as far as innings, but as we get closer to the end Spring Training, we'll start getting their innings up so they'll be ready for the regular season. It will go outing by outing, that's the way I see it. So far their arms are feeling great. We are going to treat them like any healthy pitcher we have."

Extra catcher added
The Rangers have signed veteran catcher Adam Moore to a Minor League contract with an invitation to Spring Training, according to a source. The deal is pending a physical, and Moore is not expected in camp until Saturday.
He is being brought in as an extra catcher. He will be one of three non-roster catchers with big league experience, joining Jett Bandy and Tony Sanchez.
Moore, who was drafted out of Texas-Arlington in 2006, has played in parts of nine seasons in the big leagues, including eight games with the Rays last year. He played in 60 games for the Mariners in '10, the only time he has made more than nine appearances in a season in the big leagues.
Rangers ponder Mathis workload
Rangers catcher Jeff Mathis has an excellent reputation for defense and being able to work with his pitchers. But he is also 35, and there is still some question about how many games he can start behind the plate. He started 61 games at catcher for the D-backs last season and has started more than half his team's games (81) once in his 14-year career. That was with the Angels in 2008, when he started 90.
"That's a tough one," Rangers manager Chris Woodward said. "If all goes well, you are looking at the 80 mark. It just depends. You got to factor in his age; he keeps himself in great shape, so I don't think he's going to burn out. But at the same time, he hasn't caught that many games, so you have to be mindful of that and be careful that."
• Mathis to mentor pitchers, catchers
Rangers beat
• Infielder Christian Lopes, who spent last season at Triple-A Round Rock, is limited because of a strained left oblique. He is in camp early although position players don't have to report until Sunday.
• Rangel has a long history with Zach McAllister from their time in the Indians' organization. It's a relationship to watch. McAllister had a 2.99 ERA as a reliever from 2015-17 before falling to 4.97 in 41 games for the Indians last year and getting released. Rangel was with the Giants' organization last year.
• Willie Calhoun, on competing with Hunter Pence for a possible roster spot, "I don't look at it too much, because I feel like I'm in a race with myself. I start looking at other things like that and I won't be able to focus on other stuff that I have to do, so I just feel like I'm in a race with myself, and trying to focus on everything that I have to do, and going out there and being everything I can. That's what I'm trying to focus on this spring."