Cameron Maybin was on first with no outs when James McCann hit a Texas Leaguer to center field. The ball looked uncatchable, but as Maybin neared second base, Kiermaier closed on the ball. He dove at the last second and appeared at first to have made the catch.
But the ball popped loose, and Kiermaier came up writhing in pain while holding his left arm.
The Rays' center fielder immediately started for the dugout and was met halfway by Rays trainers.
Bill Chastain has covered the Rays for MLB.