Dunning (ankle) was activated from the 15-day injured list and will start Tuesday's game in Seattle.
Dunning was sidelined the past couple weeks with a right ankle impingement, but he will rejoin the Rangers' rotation Tuesday. The 27-year-old covered five innings during his rehab start in the rookie-level Arizona Complex League last week, so he shouldn't face significant workload limitations in his first game back in the majors.