Hales logged a 2.10 ERA, 1.13 WHIP, 31 strikeouts and four saves in 30 innings across 24 appearances for Double-A Frisco.
The Rangers selected Hales, a pure relief prospect, in the fourth round last year and he has largely looked the part of a late-inning arm. At 6-foot-4, 220 pounds and armed with an upper-90s fastball that touches 100 mph, Hales is an intimidating presence on the mound. If he can find a way to miss more bats with his mid-80s slider, Hales could eventually be a closer.