Adrian Gonzalez rates right alongside Albert Pujols and Ryan Howard as one of the game's pre-eminent power-hitting first basemen. This, despite the fact that he played half of his games over the last five seasons in the pitcher friendly Petco Park.
If Gonzalez had played in a hitter's park (like Fenway Park), his numbers would have been gargantuan.
From 2008-10, Gonzalez hit 37 home runs at Petco Park. That might not sound like a lot, but it is, considering that Petco is, by far, the worst National League park for a left-handed power hitter.
Baseball Info Solutions uses a metric called "Park Factor" that compares the numbers of teams and their opponents at home and on the road. From 2008-10, Petco's "Park Factor" for lefties was 59 (on a scale of 100).
Adrian Gonzalez Home-Road Splits
Last 5 Seasons (2006-10)
If Adrian Gonzalez is indeed moving out of Petco Park, it can only do wonderful things for his production, as Petco has dragged down his numbers since he arrived in San Diego in 2006.
To calculate how many home runs Gonzalez would have hit at a ballpark that treated lefties in a neutral manner, take the 37 home runs he hit and divide by .59. Take that total (62.7) and adjust it to Fenway Park, which had a "Park Factor" of 88 from 2008-10. Multiply 62.7 by .88
Based on those calculations, the 37 homers that Gonzalez hit at Petco over the last three seasons is equivalent to a left-handed batter hitting 55 home runs at Fenway Park.
Over the last five seasons, Gonzalez hit 62 opposite field homers. According to Hit Tracker, only three would not have been home runs in Fenway Park. In fact, all 22 of his opposite field home runs hit at Petco since 2006 also would have been home runs in Boston, despite the dimensions and height of the Green Monster.
Defensively, Gonzalez will be a downgrade at first base from Kevin Youkilis.
Again, according to Baseball Info Solutions, Gonzalez rated as an average/below-average defender in four of his five seasons with the Padres. Last year, his plus/minus rating was -1, which estimates that he made one fewer play than the average first baseman. Youkilis has rated as an above-average defender at first base in each of the last five seasons, and last year had a +5 rating.
Last year, Gonzalez's main issue was on balls to his right, where he had a -8 rating; however, this might not be a significant problem in Boston, since Dustin Pedroia had a +3 rating on balls to his left in 2010.
Youkilis in all likelihood will move back to third base with the addition of Gonzalez. Youkilis played nearly 500 innings at third in 2009, and was above-average with a +10 rating. That’s better than Adrian Beltre, who was +8 last season.
(Derek Czenczelewski, Justin Havens, Katie Sharp and Mark Simon contributed to this post.)