Houser's removal from his outing Monday against the White Sox due to thumb tightness was purely precautionary, Adam McCalvy of MLB.com reports.
General manager David Stearns didn't sound particularly concerned following the game, and the pitcher himself echoed similar sentiments Tuesday. It remains to be seen when he'll get back on the mound, but it doesn't sound as if a trip to the injured list to start the season is likely.