Hearn will be on the Rangers' Opening Day roster, Levi Weaver of The Athletic reports.
The 26-year-old has made five appearances in spring training and given up five earned runs on eight hits with six strikeouts and six walks over 10.2 innings. Hearn's exact role remains unclear, as the Rangers have floated the idea of utilizing tandem starters at the back end of the rotation, but he'll at least have a spot on the major-league roster.