I haven't confirmed the terms yet, but one industry source said the deal is in the neighborhood of $16 million.
UPDATE AT 10:30 P.M.: The deal is actually worth $15 million, and as the Washington Post first reported, there's a $10 million option for 2013 with a $1 million buyout, bringing the guaranteed compensation to $16 million. LaRoche still has to take a physical, but people in the Nationals organization have been expecting the deal to get finalized for days.
The move gives the Nationals a first baseman for the next two seasons, and a left-handed bat to go somewhere in the middle of the lineup. My immediate guess is that LaRoche will bat fifth, between Jayson Werth and whoever's playing left field. Michael Morse can now platoon with Roger Bernadina in left, and the Nationals' lineup gets some much-needed length. He's a notorious slow starter, but he represents a defensive upgrade over Adam Dunn, and is known around the game as a good receiver at first.
LaRoche's signing means Chris Marrero is effectively blocked at first base until he's at least 24, and if there was already growing doubt around the game that the 2006 first-rounder will ever start at first for the team, there's a mountain of it now. I'll have more on those ramifications tomorrow, but in the meantime, the move should help the Nationals toward being a competent team in 2011.