Neither Lo Duca nor general manager Jim Bowden were available for comment.
The right-handed-hitting Lo Duca played with the Mets the last two years. In 2007, Lo Duca hit .272 with nine home runs and 54 RBIs. He also helped guide New York to the National League Championship Series against the Cardinals in 2006.
Lo Duca, 35, will be the everyday catcher for Washington, while Jesus Flores will be the backup. If Flores needs to develop in the Minor Leagues, then Humberto Cota and Chad Moeller will battle for the backup job.
The Nationals have been looking for a starting catcher since they traded Brian Schneider to the Mets on Nov. 30. During the Baseball Winter Meetings in Nashville, Tenn., Lo Duca, Johnny Estrada and Damian Miller were among the free-agent catchers who were considered to join the Nationals. In fact, toward the end of the Meetings, there were multiple reports that Lo Duca was going to sign with the Blue Jays, but Lo Duca changed his mind and the Nationals found themselves back in the mix.
In Lo Duca, the Nationals are getting a four-time All-Star who is known to work the count. He has struck out no more than 54 times in one season. He also is known to play hurt and will speak his mind.
"Brian was a big part of our team. I think the Nationals did a good job to go out and try as best as they could to replace him with what's out there. I think Paul is one of the smartest players in the game," said Nationals third baseman Ryan Zimmerman.
Lo Duca began his career with the Dodgers in 1998 and was given his first chance to start in 2001, when he hit a career-high .320. Lo Duca was with the Dodgers until July 30, 2004, when he was traded to the Marlins in a six-player trade.
Lo Duca would play a full season with Florida in 2005 before being traded to the Mets after that season.
"He is a stand-up guy. He is not afraid to let people know how he feels if somebody is not going about their business the right way out there," said one baseball source.
Mets general manager Omar Minaya praised Lo Duca for the job he did for New York the last two years.
"He was a good teammate. Offensively, he made contact and grinded his at-bats. His teammates in Washington are going to like him," Minaya said.
The Lo Duca signing means that he will be re-united with Nationals manager Manny Acta. The two worked together for one year when both were with the Mets in 2006.
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.