Howard (shoulder) was activated from the 15-day injured list and optioned to Triple-A Round Rock on Thursday.
Howard appeared in four games with Round Rock during his rehab assignment, and he'll remain with the affiliate now that he's been fully cleared from the right shoulder impingement that put him on the IL in early August. The 26-year-old has appeared in 10 games for the Rangers this year and has a 7.41 ERA, 1.73 WHIP and 32:15 K:BB across 37.2 innings.