"Too early to tell, but he didn't look good coming off the field," Astros manager A.J. Hinch said. "As he walked off the field, he was a little uncomfortable. He got in the tunnel and did a few tests and deemed he wasn't 100 percent, and so I went with the healthier [A.J.] Reed."
Gonzalez has been one of the Astros' biggest weapons this season because of his versatility, though he had a tendency to get banged up. A switch-hitter, he's started 58 games at first, 15 at third, 10 in left, five at shortstop and six at second base.
Houston is expected to call up some extra players beginning Friday when rosters expand, so they might be forced to make a move to get another infielder if Gonzalez is going to miss a few days of action. It wasn't clear exactly when Gonzalez injured the hamstring.
Brian McTaggart has covered the Astros /since 2004, and for MLB.com since 2009. Follow @brianmctaggart on Twitter and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.