There's been an occasional mini-debate in the comments about the relative useful/less-ness of right-handed and left-handed hitters when asked to play 81 of their games in Wrigley Field; the specific question being whether the benefits of adding left-handed power to the Cubs' lineup are negated by any disadvantages their home park might hold for them.

No doubt those who swing from starboard have a decided advantage in Wrigley when it comes to lofting it out of the park (according the lefty/righty park factors from the 2005 version of The Bill James Handbook, right-handers have a factor on home runs of 137, with 100 being average), but the debate got me wondering whether the disadvantage for Cub port-siders was enough to discourage their use.

I decided to quickly look at this with the two park factor elements the book had splits on: batting average and home runs. The catch is that we can't just look at the 81 games that would be played at home, we have to account for the other 81 games and the park factors that would be at work in each of those contests to know what the effect is over the course of a season.

For ease of use, I assumed a player who would hit .300 with 30 homers over 162 games in a neutral park. From there, using the three year (2002-2004) park factors for each stadium and the Cubs' 2005 schedule, determined how this fictional character would do in each setting with each type of handedness, weighted it by the number of games they would play there, and compiled all the numbers together to get figures for the season as a whole (in the case of the Nationals, since there are no numbers from 2002-2004 for RFK, I assumed a neutral park for the three games the Cubs will play there). The results are below:

	Lefty	Righty	Difference
HOME AVG	.285	.300	.015
HOME HR	14.6	20.6	6.0
ROAD AVG	.301	.298	-.003
ROAD HR	15.0	14.9	-0.1
TOTAL AVG	.293	.299	.006
TOTAL HR	29.6	35.5	5.9

Remember in looking at this that our starting point for the season was a player who hit .300/30 in a neutral environment. A lefty Cub with that baseline actually makes out alright, taking most of the hit on batting average, and all of it from his home park. So that we're clear, assuming 540 at bats in a season with half of them coming at home, the .015 difference in batting average you see between him and the right-hander amounts to 4 hits over 81 games.

Where the difference really comes in is with those homers, and it's not how few the lefty hits but how many the righty does that accounts for the disparity. The very slight advantage the lefty has during the road games is completely trumped by the six home run advantage in Wrigley received by the right-hander.

Therefore, assuming a neutral base, and the Cubs' 2005 schedule, a right-handed hitter should hit for better average and better power as expressed by home runs than his left-handed counterpart. However, it's important to note that when the Cubs put a lefty on the field every day, they get production over the course of a season that's very close to what they could expect in a neutral environment, meaning that there is no inherent disadvantage to playing a lefty, but instead, a large advantage with a right-hander at the dish.

So, to answer the original question, judging from the limited information above, the benefits of adding left-handed power to the Cubs' lineup are not negated by the disadvantages of their home park. Wrigley, in fact, does not look to be terribly hard on lefties. However, if the lineup isn't already leaning heavily to the right, and there's a choice between a left-hander and right-hander of equal ability, it appears the clear choice is the righty.