The affect of weather on JD Drew's power
From SoSH
Overview
Some analysis on Drew's power potential when he makes the move to Fenway:
The aerodynamic model behind Hit Tracker allows me to isolate the impact of wind, temperature and altitude on batted balls from the actual striking of the ball - in other words, if a ball flies 395 feet into the stands, I can figure out how many feet of distance came from the wind, and how many from the ambient temperature, and how many from the altitude. These impacts are all indexed to a set of standard conditions which are zero wind, 70 degrees F and sea level altitude.
Having analyzed 19 of J.D. Drew's 20 homers from 2006 (the other one I couldn't pick up the exact landing point, but FWIW it was approximately 355 feet in length, straight down the RF line), I can say what the atmospheric effects were on those 19 homers. Here they are:
Home Run Chart
| Date | Ballpark | Actual Dist | Wind | Temp | Alt | Total Impact | Standard Dist |
| 4/4/2006 | Dodger Stadium | 412 | 10 | -5 | 3 | 8 | 403 |
| 4/21/2006 | Dodger Stadium | 396 | 18 | -4 | 4 | 18 | 378 |
| 4/23/2006 | Dodger Stadium | 425 | -22 | -3 | 4 | -21 | 445 |
| 4/24/2006 | Minute Maid Park | 341 | 0 | 3 | 0 | 3 | 337 |
| 5/2/2006 | Chase Field | 391 | -6 | 3 | 8 | 5 | 386 |
| 5/2/2006 | Chase Field | 373 | 3 | 2 | 7 | 12 | 360 |
| 5/9/2006 | Dodger Stadium | 386 | 11 | -2 | 3 | 12 | 373 |
| 5/20/2006 | Dodger Stadium | 404 | 17 | 1 | 3 | 21 | 383 |
| 6/1/2006 | Dodger Stadium | 383 | 19 | 2 | 3 | 24 | 359 |
| 7/28/2006 | Dodger Stadium | 400 | 22 | 4 | 4 | 30 | 371 |
| 7/30/2006 | Dodger Stadium | 403 | 19 | 4 | 4 | 27 | 377 |
| 8/20/2006 | ATT Park | no data | no data | no data | no data | no data | no data |
| 8/25/2006 | Chase Field | 411 | 0 | 4 | 8 | 12 | 400 |
| 8/25/2006 | Chase Field | 416 | 0 | 4 | 8 | 12 | 405 |
| 9/2/2006 | Dodger Stadium | 416 | 1 | 5 | 4 | 10 | 406 |
| 9/14/2006 | Wrigley Field | 376 | -30 | 0 | 4 | -26 | 402 |
| 9/18/2006 | Dodger Stadium | 417 | 9 | 4 | 4 | 17 | 401 |
| 9/20/2006 | Dodger Stadium | 411 | 11 | -2 | 4 | 13 | 398 |
| 9/22/2006 | Dodger Stadium | 423 | 7 | 0 | 3 | 10 | 413 |
| 9/29/2006 | ATT Park | 398 | 43 | -5 | 0 | 38 | 361 |
Home Run Analysis
On his 2006 home runs, Drew picked up an average of 11.8 feet of distance from atmospheric conditions, as compared to 70 degree days at sea level with no wind. How does this compare to the average conditions at Drew's home park, Dodger Stadium, Fenway Park and the site of Drew's career year (2004), Turner Field?
Turns out Fenway Park is a lot less favorable for hitters than either of those two parks: here is the average impact on a 400 foot fly ball in each park in 2006, further broken down by direction (LF/CF/RF). Impact is in feet added or subtracted to a fly ball.
Dodger Stadium: +9.8 / +16.0 / +11.3 Turner Field: +7.8 / +9.8 / +8.3 Fenway Park: -0.4 / +4.1 / +2.7
So, on an average day in Dodger Stadium in 2006, the same home run ball in Dodger Stadium flew 10 feet further to LF, 12 feet further to CF and 9 feet further to RF than it would have in Fenway Park. That is a significant effect, particularly when you recognize that Fenway Park is deep in RF and RCF, and that 16 of Drew's 2006 homers were hit to the right-field side of straight-away CF.
Let's not forget that a player only plays half his games at home. So, here are the average atmospheric impacts during Dodgers road games and Red Sox home games: (again, LF/CF/RF impacts in feet)
Dodgers road games: +6.7 / + 11.4 / + 11.1 Red Sox road games: -1.9 / +1.4 / +3.0
No matter how you look at it, Drew enjoyed much more favorable atmospheric conditions in 2006 than he would have had he played for Boston last year.
What is the potential impact of Drew's losing 10-12 feet of distance on his fly balls? Hit Tracker also allows me to take a homer hit in one park and one set of atmospeheric conditions, and place that homer in another park and another set of atmospheric conditions, and see what the result would have been.
I did that for Drew's 20 homers, and what I found was that Drew would have fared significantly worse had those 20 balls been struck at Fenway Park. I put the 20 hits in 70 degree weather with no wind, which is slightly less favorable than the average conditions from 2006 (as was shown earlier), and got the following results:
11 HR's 7 Flyouts 1 probable 3B (line drive to the triangle) 1 flyout/double (definitely in the park to CF, debatable whether it would be caught)
Now, looking only at his homers is a bit of a cherry-pick, in that Drew may have hit some long fly-ball outs to LF at Dodger Stadium or elsewhere that might have scraped (or cleared) the Monster at Fenway. So in a move to the Sox, Drew probably gains a bit as well, but a nearly 50% drop in homers from the 20 that actually cleared the wall in '06 worries me - that's a pretty serious reduction in power.
Summary
- J.D. Drew's success in 2006 was greatly influenced by highly favorable atmospheric conditions during Dodger games, both home at Dodger Stadium and on the road.
- Drew will probably not enjoy the same assistance from the elements if he plays for Boston in 2007.
- If Drew hits the ball the same way in 2007 that he did in 2006, he will see his home run total (and other related stats) drop significantly.
- We Red Sox fans should calibrate our expectations for Drew. He will probably not hit as well in a Red Sox uniform as he has for the Dodgers and Braves.
Let's hope Drew learns to love the Green Monster - it is the one hope I have for him having a strong season in a Red Sox uniform. Drew has shown some oppo power in the past, and lots of other players have adjusted their game to take advantage.
