Harrison allowed three hits and one run over 4 2-3 innings Tuesday for Double-A Frisco. The left-hander struck out three with no walks, five days after his start in the RoughRiders' season opener was shortened by rain.
The Rangers' opening day starter in 2013 is penciled in for an April 23 return. He made only two starts last season before two operations for a herniated disk in his back, then had a setback with neck and back stiffness.
Harrison said the 62-pitch outing was the best he's felt so far in the rehab process. He is scheduled to make two more rehab starts.