ARLINGTON -- Rangers right-handed reliever Chris Martin was optioned to Triple-A Round Rock on Tuesday prior to the club's series opener against the Astros at Globe Life Park.
Martin is 1-1 with a 4.13 ERA in 27 appearances this season. He last pitched Saturday, when he threw a scoreless inning against the White Sox.
The move made room on the 25-man roster for first baseman Ronald Guzman, who returned from the seven-day concussion disabled list on Tuesday, the first day he was eligible to return.