The person spoke early Wednesday on condition of anonymity because the agreement was not yet final.
Uggla was acquired from Florida in November for infielder Omar Infante and left-hander Mike Dunn. Eligible for salary arbitration, the two-time All-Star turned down a $24 million, three-year offer from the Marlins last summer.
Uggla batted .287 with 33 homers and 105 RBI last season, when he made $7.8 million. Without the new deal, he would have been able to become a free agent after the 2011 World Series.
RANGERS: Adrian Beltre is taking over as the everyday third baseman for Texas, and Michael Young is switching positions again.
The AL champion Rangers introduced Beltre as their new third baseman Wednesday after agreeing on a $96 million, six-year contract with the All-Star.
The Rangers can void the final season if Beltre fails to have either 1,200 plate appearances in 2014-15 combined or 600 in 2015.
NATIONALS: A person familiar with the negotiations tells The AP that the team and free-agent first baseman Adam LaRoche have agreed to a two-year contract, pending a physical.
Speaking on condition of anonymity Tuesday night because the deal had not been completed, the person said the agreement contains a mutual option for 2013.
BREWERS: Finalized their $1.75 million, one-year contract with former Braves reliever Takashi Saito .
The right-hander can earn an additional $1 million in performance bonuses based on games and $500,000 for days on the active roster.
RED SOX: A person familiar with negotiations says Boston has agreed to a minor league contract with right-handed reliever Tony Pena Jr , the son of former Red Sox catcher Tony Pena .
The person spoke on condition of anonymity because the team has not made an announcement.
ORIOLES: Shortstop Cesar Izturis finalized a $1.5 million, one-year deal.