Floyd, sidelined for most of August and part of September, singled to left field with two outs and chugged around the bases when Shawn Green's high fly ball to left field caromed off the top of the fence.
Floyd began limping as he rounded third base but slid into home for the Mets' fourth run of the game. The Mets' training staff tended to Floyd in the dugout, but he was unable to continue and was replaced in the field by Endy Chavez.
A club official announced in the fourth inning that Floyd had a "stretched left Achilles" and was listed as day-to-day. Two innings later, the Mets announced that an exam by the team physician showed that Floyd had strained the tendon, not torn it, and would be re-evaluated after the game.
The National League East champions already are playing the NL Division Series without starting pitchers Pedro Martinez and Orlando Hernandez.
Floyd, who batted .244 with 11 home runs and 44 RBIs, had one at-bat between Aug. 2 and Sept. 3.
He has been an offensive factor in the best-of-five Division Series against the Dodgers, hitting a solo home run in the Mets' Game 1 victory, singling and scoring a run in the Game 2 win and singling during a three-run first inning against Greg Maddux in Game 3.
Jim Street is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.