PHOENIX -- The Rangers are likely going with a 13-man pitching staff to open the regular season after optioning Willie Calhoun to Triple-A Round Rock on Tuesday.
A 12-man staff is considered normal in the Major Leagues. A 13-man staff would possibly allow Bartolo Colon and/or Jesse Chavez to make the Opening Day roster.
"We initially came in looking at both scenarios, probably leaning toward 13 and still on that side of it," Rangers manager Jeff Banister said. "However, there's some situations where we could go 12."
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A 13-man staff would include eight relievers in the bullpen. That unit already consists of left-handers Jake Diekman and Alex Claudio, and right-handers Keone Kela, Tony Barnette, Matt Bush and Chris Martin. Timothy Lincecum could be the seventh reliever if the Rangers feel he can be ready by Opening Day.
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That would leave one more spot in the bullpen for Chavez as a long reliever and swing starter. The other possibility is Colon making the rotation and Mike Minor going into the bullpen.
There are other candidates. Nick Gardewine has allowed just one run in 6 1/3 innings, and Jose Leclerc has showed significant improvement with his command. Kevin Jepsen has allowed one run in six innings
It's a tough camp. Austin Bibens-Dirkx was the Rangers Rookie of the Year in 2017 and has not allowed an earned run in his last seven innings. His ERA and WHIP are both 1.13 in eight Cactus League innings. He was sent to the Minors on Tuesday.

Nicholas returns to Rangers
Catcher Brett Nicholas is returning to the Rangers after clearing waivers and being assigned to Triple-A. Nicholas, who was designated for assignment last week, will rejoin the Rangers in big league camp as a non-roster invitee.
The move comes on the same day that the Rangers optioned catcher Jose Trevino to Double-A Frisco. Trevino spent all of last season with Frisco, but the Rangers want him to get consistent playing time.
The Rangers will likely staff their Triple-A roster with veteran catchers who can be ready to step in at the Major League level when the need arises. Nicholas is one of them. The Rangers have three veteran catchers in camp fighting for the backup job behind Robinson Chirinos. Juan Centeno is on the 40-man roster and out of options. Curt Casali and Michael Ohlman are in camp as non-roster invitees.
Blackburn hopes for best
Pitcher Clayton Blackburn is waiting to see what happens Thursday when he is examined by Dr. Keith Meister, but it doesn't look good. Blackburn had to exit Monday's start against the Indians in the first inning with tightness in his right elbow.
"I felt tight the last 2-3 days, but that is nothing uncommon," Blackburn said. "I thought it was middle-of-Spring Training soreness. But it is more than that. Even if I was having a bad spring, it's never good to get this. I am hoping for something I can rehab and be back before the All-Star break."
Hamels on Arrieta
Cole Hamels, who allowed one run in four innings against the Brewers on Tuesday, was glad to see the Phillies sign free-agent pitcher Jacob Arrieta. Hamels pitched for the Phillies in 2006-15, and his trade to the Rangers in '15 was a big part of their rebuilding.
"It's nice to see these free agents finally signing, because I know they want to play," Hamels said. "This has been an unusual winter time. I guess they will be excited. Philly has some good pitchers, and they have a lot of young guys who can learn from Arrieta. They are making strides and trying to be competitive. It's a fun sports city to play for. I know they have been champing at the bit to get relevant again. That's definitely going to put them on the map."
Hamels said he doesn't follow the Phillies.
"I think there is only one guy left that I played with … Aaron Nola," Hamels said.
Rangers beat
• Bush, pitching against the Brewers, allowed a two-run home run to Jesus Aguilar in his first appearance since being put back in the bullpen.
• Chris Martin has not allowed a run over five appearances and has retired the last nine batters he faced.
• The Rangers have stolen a base in six straight games. Centeno had the steal on Tuesday. He has never had one in a regular-season game in the Major Leagues.
Up next
Right-hander Doug Fister makes his second start of the spring on Thursday against the Brewers at 3:05 p.m. CT in Surprise. Fister threw three scoreless innings against the Mariners on March 4. His last outing was in a simulated game. You can listen to the game through an exclusive audio webcast on rangers.com.