Sammy Sosa hit a whopping .387/.569/.882 against LHP in 2001.
The Brewers have stated over and over this offseason that they have two goals. One is to acquire a "contact" hitter. The second is to acquire a left- handed starter. Looking at the Brewers last year, it's obvious to everyone why the Brewers need to upgrade their ability to get on base and hit for average, although I hardly think one player alone is going to totally turn the offense around.
The second goal is a little more up in the air. The Brewers do need to improve their pitching staff, which ranked 11th in the NL in runs allowed. Moreover, their bullpen showed definite signs of wearing down as the season went on and the Brewers starters proved unable to work deep into games on a consistent basis. But the question is, do they specifically need a lefty or will any quality pitcher, regardless of which hand he throws with, do?
One of the reasons to acquire a left-hander is to take advantage of park effects like a "short porch" in right field and a deep left field. But Miller Park is nearly symmetrical sporting dimensions of 344 feet, 371 feet, 400 feet, 374 feet, and 345 feet from left field to right field. And prevailing winds are certainly not a factor in Miller Park. It's pretty hard to argue that there is any structural reason to suspect that a left-hander will have an advantage in Milwaukee.
However, looking at park effects, as provided by STATS, Inc., there's some indication that Miller Park may favor left-handed hitters, although the statistical sample is small. Left-handed batters hit 85 home runs in Miller Park (41 by the Brewers, 44 by their opponents) while the Brewers and their opponents combined to hit 70 away from Miller Park (40 by the Brewers, 30 by their opponents) for a Park Factor of 133 for LHB home runs. That's a very significant factor in favor of left-handed batters. The question is whether it's real or a statistical fluke? The HRs hit by the Brewers would suggest that it's pretty much a statistical fluke. Maybe Brewer pitchers weren't as intimidated away from Miller Park in more pitcher friendly environments? Or there possibly is an advantage to lefties, maybe involving hitting backgrounds. One-year park factors are notoriously flukey, so I think more data is necessary to make a solid conclusion.
With the advent of the unbalanced schedule, the Brewers now play opponents in their division much more often than before. And since the Brewers have to finish 2nd in the division to have any shot at the playoffs, it's useful to look to see if teams in the division hit lefties worse than righties.
|NL Average (vs. all pitchers)|| .261/.331/.425|
Let's see two teams in the division, Astros and Cubs led by Sammy Sosa who hit a whopping .387/.569/.882 against lefties, are well above average against left-handers, one team, Cardinals, is above average vs. lefties, one team, Reds, are below average vs. lefties, and one team, Pirates, is horrible against left-handers. All in all, it seems that 3 out of 5 opponents in the division gain an advantage against the Brewers if they add a lefty.
A Different Look?
Does adding a lefty to a rotation make the whole greater than the sum of its parts by adding a different "look" to the staff? Frankly, I don't believe there's any way to objectively measure this effect given all of the other factors that go into a pitching staff. Just looking at the staff with the most dominant lefty in the game, the Arizona Diamondbacks with Randy Johnson, the results look inconclusive. Sure Curt Schilling had the best year of his career, but was it because of the presence of Randy Johnson or due to Schilling, a very good pitcher before he got to Arizona, simply having a career year? Johnson's presence didn't seem to have any effect on the back 3/5ths of the Diamondbacks' rotation and the bullpen which were both below average overall. Even if there is an effect, I think it's safe to conclude that in an era of advanced scouting, videotapes, and Abner pitching machines which can basically duplicate any pitcher, the effect is less than it's ever been and getting smaller.
After looking at the pros and cons of acquiring a lefty starter, there certainly doesn't appear to be any overwhelming reason for paying a premium to acquire one. Not with the way the Astros, Cubs, and Cardinals hit lefties anyway. The advantage to having a lefty starter is basically in a short series against the Reds and Pirates or the like. However, unless the Brewers are very adept at juggling the rotation, which has its own hazards, any lefty they acquire is also going to have to face the teams that hit left-handers better than league average over the course of a season. Overall, what is going to matter most is if the Brewers can acquire a good, durable pitcher to upgrade the rotation, not which hand he throws with.