Adrian Gonzalez, Red Sox finalize seven-year contract extension

It's official.

The Red Sox and first baseman Adrian Gonzalez have completed a seven-year contract extension worth $154 million, per Ian Browne of MLB.com.

The extension, which is the second-largest in team history, keeps Gonzalez, who was due to enter free agency after the 2011 season, in Boston through the 2018 season.

As Browne points out, there were two main reasons for waiting to announce the deal. First, it allowed the Red Sox to make sure there were no lingering effects from his off-season shoulder surgery. Second, the Red Sox saved $6.2 million in luxury tax by announcing the deal after the season started.

Gonzalez is off to a slow start -- .268 with one homer and seven runs batted in over 11 games.

With playing half of his games a park much more hitter-friendly than his previous home (Petco Park), however, Gonzalez should be in store for huge numbers year in and year out.

Here are his career splits:

• Home: .263, 199 runs, 61 homers (140 extra-base hits), 216 RBIs in 431 games
• Away: .303, 294 runs, 108 homers (226 extra-base hits), 316 RBIs in 438 games

Over the five-year period (2006-2010) he spent in San Diego, Gonzalez ranks sixth in baseball in home runs (161), eighth in runs batted in (501) and fifth in total bases (1,529).