Smith exited Monday's game against the Astros in the bottom of the sixth inning due to an apparent injury, Martin Gallegos of MLB.com reports.
The Athletics were held without a hit for the first five innings of Monday's matchup, but Smith led off the bottom of the sixth inning with a double. However, the 25-year-old slowed down as he headed into second base and left the game with a trainer. The exact nature and severity of his injury aren't yet clear.