"It's great to be here," LaRoche said. "I love the direction this team is going and what [general manager] Mike [Rizzo] has done so far. I think this is a great start. It's going to be a fun year, and we're 30 days away [from Spring Training], so I think we're all ready to get after it."
The Nationals have been looking for a first baseman since they allowed Dunn to become a free agent. LaRoche, 31, is coming off the best season of his career, hitting .261 with 25 home runs and 100 RBIs for the D-backs in 2010. He is also an above-average defensive first baseman.
This offseason, Washington has put an emphasis on defense, which has been below average the last three years. The Nationals believe they took a step in the right direction by signing LaRoche, who has made 44 errors in 8,468 chances.
As far back as last August, the Nationals had interest in acquiring LaRoche's services.
"Adam is a elite defender -- a left-handed-hitting and throwing first baseman, which was a point of emphasis for us going into the offseason," Rizzo said. "He fulfills the priorities that we are seeking here. We are glad to have him."
Besides driving in runs and playing solid defense, LaRoche brings leadership skills, which he learned by watching former teammates such as Chipper Jones and John Smoltz. LaRoche was known to have those skills as a member of the Pirates.
"I think a lot of [the leadership skills] comes with some experience and getting to play in the big leagues -- now going on eight years," LaRoche said. "A lot of the guys I came up with in Atlanta were kind of my mentors -- watching Smoltz, Chipper and Andruw Jones and the way Bobby Cox -- as a manager -- handled his club.
"To see that for three years was really as good as it gets -- seeing how the game is supposed to be played and seeing how you're supposed to handle yourself on the field, in the clubhouse, when it comes to dealing with the media, you name it. So I came up in some pretty good hands, and I've been lucky now to be able to pass that on to some younger guys."
LaRoche has played in the big leagues for seven seasons. He is best known for playing with the Braves, but he has also spent time with the Red Sox. During those seven years, LaRoche is a .271 career hitter, with 161 home runs and 569 RBIs.
He is one of just five big leaguers to have hit 20-plus home runs as a first baseman each of the last six seasons. He is joined on this list by Albert Pujols, Mark Teixeira, Paul Konerko and Ryan Howard.
LaRoche, who has also legged out 30 or more doubles five straight years, will hit cleanup or fifth in the lineup.
"It'll be nice to help protect [Zimmerman and Werth] a little bit," said LaRoche. "But I've always said I like being in a position where I can drive in runs. I've been on teams where that's happened in the three-, four-hole. There's been teams where I've hit sixth and had plenty of opportunities. So yeah, depending on how we work it, I think we can all help each other, help protect each other and feed off of that."
LaRoche comes from a baseball family. His father, Dave, was a solid relief pitcher for the Angels, Yankees and Indians in the 1970s and '80s, while his brother, Andy, played third base for the Pirates the last three years before becoming a free agent.
Adam is hoping that Andy, a third baseman, can play for the Nationals, but Adam said he has no control over where his younger brother plays. Adam pointed out that three American League clubs have interest in Andy. The siblings played together in Pittsburgh in 2008 and '09.
"I would hope that would be a possibility," Adam said about Andy joining the Nationals. "I can put in a good word for him. ... Seeing him across the diamond and sharing a locker right next to him was unbelievable."