WEDNESDAY: Dodgers GM Ned Colletti has officially announced Mattingly's extension to reporters, including Dylan Hernandez of the Los Angeles Times (Twitter link).

TUESDAY: The Dodgers and manager Don Mattingly have agreed to an extension that will keep him in the Dodgers' dugout for the next three seasons, according to ESPNLosAngeles.com's Ramona Shelburne. An official announcement is expected later this week. Ken Rosenthal of FOX Sports (via Twitter) reported yesterday that the two sides were closing in on a deal.

Mattingly was already under contract through the 2014 season thanks to a $1.4MM option that vested when his Dodgers defeated the Braves in the NLDS. However, Mattingly made his desire for a multiyear contract known shortly after the season in a surprisingly candid press conference. Mattingly has led the Dodgers to three straight winning seasons, including an NL West Division Championship and an NLCS berth in 2013.

His job was called into question earlier in the season when the Dodgers were struggling despite the team's gaudy payroll, but Mattingly – thanks to some improved health and the emergence of Yasiel Puig – silenced critics by helping the Dodgers to a 42-8 run that vaulted them to the top of the NL West. Shelburne reported back in November that the two sides were discussing a multi-year deal and it sounds like they've finally hammered it all out.

Steve Adams contributed to this post.