Martin (shoulder) was sent to Double-A Frisco on Sunday to begin a rehab assignment.
Martin landed on the 15-day injured list June 1 due to a right shoulder impingement. The 40-year-old right-hander may need more than one appearance in the minors to knock off his rust, but he shouldn't be in line for an extended stay on the farm before slotting back into the Texas bullpen. Martin has two wins and one hold this season in 12 appearances to go along with a 7.84 ERA, 1.94 WHIP and 7:2 K:BB over 10.1 innings.