Brocail said all candidates should have three more outings before the Rangers break camp.
"Those next three starts should separate somebody," Brocail said. "If you're using Spring Training to get in shape, now is the time to win a job. Guys know that. We have enough good arms in the organization, we'll be fine."
The race is likely down to right-handers Nick Martinez, Chi Chi Gonzalez, A.J. Griffin and Jeremy Guthrie and left-hander Cesar Ramos. Gonzalez and Griffin are both scheduled to start on Saturday, against the D-backs (Scottsdale) and Royals (San Antonio), respectively.