WASHINGTON — Gavin Floyd, recently returned from Tommy John surgery, pitched six scoreless innings Thursday night before leaving with an elbow injury, the latest setback for an injury-riddled Atlanta Braves' rotation and one that tempered a 3-0 victory over the Washington Nationals. Floyd flexed his pitching arm awkwardly after giving up a long foul ball to Jayson Werth on the first pitch of the seventh inning. The Braves trainer went to the mound, examined Floyd's elbow and then he left the game for reliever Anthony Varvaro.