Martin (forearm) will begin a rehab assignment at Double-A Frisco on Monday.
Martin, who last pitched April 30 before hitting the 10-day disabled list, may need to make a couple of appearances in the minors before the Rangers are comfortable adding him back to the active roster. Prior to allowing four runs in the April 30 outing, Martin had been one of the Rangers' top late-inning options, producing a 2.70 ERA and 1.20 WHIP over his first 15 appearances of the season.