SAN FRANCISCO -- Nationals catcher Wilson Ramos left Tuesday's 2-1 victory over the Giants in the top of the ninth inning Tuesday because of right hamstring tightness. For now, he is listed as day to day. The Nationals hope to know how serious the injury is by Wednesday.

Wilson hurt the hamstring after batting in the ninth inning against right-hander Juan Gutierrez. Ramos doubled to left-center field and felt pain as he was sliding into second base. Ramos left the game and was replaced by outfielder Nate McLouth. Ramos walked back into the dugout on his own power.

After the game, Ramos was upbeat and said he wasn't as worried as much he was in the past regarding hamstring injuries. Ramos missed half of last season because of left hamstring injuries.

"I felt something in the hammy, but it's not that bad," Ramos said after Tuesday's game. "Hopefully, I will feel better tomorrow. We'll see how it feels tomorrow. When I felt it, it scared me. That moment I said, 'It's happened again.' I'm thinking positively."