Dyson had a heavy work day on Wednesday with pitching coach Doug Brocail, trying to work out the mechanical issues that have plagued him early in the season. He has allowed 11 runs in three innings over his first four games.
The Rangers aren't ready to make any pronouncements on the situation in the closer's role. But the Rangers had Tony Barnette and Jeremy Jeffress on-call for that role Wednesday night vs. the Angels.
"We need Sam to be a quality pitcher," manager Jeff Banister said. "We need for him to get quality outs. We need him to be back to what he is, a quality pitcher. He has premium stuff. For us to be a quality ballclub, Sam needs to be a viable part of our bullpen."
Martinez will serve as the Rangers' long man. Mike Hauschild could see service as a middle reliever and Jose Leclerc will be used in higher-leverage situations late in the game. Leclerc has pitched in three games and opponents are 1-for-13 with no walks and five strikeouts.
Andrew Cashner threw a 40-pitch bullpen session on Tuesday as the Rangers weigh the possibility of starting him Saturday or giving him one more start in the Minor Leagues. He is on the disabled list because of soreness in his right biceps muscle. He threw 75 pitches in an extended Spring Training game on Monday and one more start in the Minors would get him up to 90.
To make room for Martinez, the Rangers optioned infielder Drew Robinson to Triple A. He had appeared in just one game for the Rangers and Banister said he needs to go play regularly.
Ross has minor setback
Right-hander Tyson Ross was scratched from a start in extended Spring Training on Wednesday because of upper back spasms. Ross was scheduled to throw 60 pitches over four innings as he continues his recovery from thoracic outlet syndrome surgery last October.
The Rangers are hoping this will not be a major setback. The plan is for Ross play catch on Thursday and possibly throw a bullpen session this weekend. If that goes well, he could get back into a game sometime next week.
"I don't think it's a big setback," assistant general manager Mike Daly said. "He hit all the checkmarks in Spring Training. Once he plays catch and does a bullpen, we'll be able to re-evaluate. He is still in a great spot."
The Rangers are hoping to get Ross into their rotation sometime mid-to-late May. This might push that timetable back no more than a week if he is able to get back on the mound this weekend.
T.R. Sullivan has covered the Rangers since 1989, and for MLB.com since 2006. Follow him on Twitter @Sullivan_Ranger and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.