Double-A Frisco placed Lopez on its 7-day injured list May 27 due to an unspecified injury.
Lopez submitted a 7.20 ERA, 1.97 WHIP and 42:22 K:BB in 35 innings over eight starts before landing on the shelf. The Rangers added the 24-year-old righty to their 40-man roster over the winter, but he didn't appear especially close to earning his first big-league call-up prior to getting injured.