Hearn will be called up from Triple-A Round Rock to serve as the Rangers' bulk-relief pitcher Friday against the Mariners, Evan Grant of The Dallas Morning News reports.
Hearn joined the Rangers taxi squad Thursday and will likely be able to handle a heavy workload after completing five innings in each of his last two starts with Round Rock. Hearn has struggled to a 5.86 ERA, 1.67 WHIP and 55:30 K:BB across 63 innings with the Rangers this season. Matt Bush will serve as the opener ahead of Hearn.