Trading Tal's Hill for Home Runs

When the Astros take the field on April 3^rd for their 2017 home opener, it will be a smaller field. Tal's Hill was removed this off-season as the center field walls were brought in from 436 ft to 409 ft at the deepest part of the ballpark. Naturally, this should result in more home runs to center field, but just how many more? Furthermore, will this change end up benefitting the Astros or hurting them?

Statcast to the Rescue

To help answer these questions, I pulled some data for fly balls hit to center field at Minute Maid Park over the last two seasons. Now, remember that the deepest part of center field was 436 ft away from home plate in 2015-2016, but not every part of center field is that same distance. So a ball could clear a different part of the center field wall without traveling 436 feet. I used Statcast data, which indicates whether a fly ball was hit to left, center, or right field, but doesn't get more specific than that. So if a ball was hit 420 feet to center field, it may or may not have been a home run depending on exactly which part of center field the ball traveled to.

When I looked at the data, I discovered that every fly ball to center field that traveled more than 426 feet cleared the fence. Since I didn't want to get too scientific with this, I stopped there. Every ball hit within 10 feet of the maximum center field distance in 2015-2016 was a home run. So let's assume the same for 2017. Again, the deepest center field wall in 2017 will be 409 feet away from home plate. So let's assume that any balls hit more than 399 feet to center field in 2015-2016 would have been home runs using 2017 ballpark dimensions.

Results

In 2015, only 7 balls traveled over 399 feet to center field without clearing the fence. That number jumped up to 18 in 2016. Our next question was to look at whether this change will help or hurt the Astros.

2017-adjusted Home Runs

While it's hard to predict the future (trust me, I'm an actuary), it does appear that the Astros would have benefited from smaller ballpark dimensions more than their opponents in 2015-2016.

Lastly, there were a couple interesting observations when looking at the specific players who hit these deep drives that didn't have quite enough to leave the ballpark:

• George Springer hit one 2017-adjusted home run in each season. While his 2016 long ball barely made the cut at 401 ft, his 2015 drive went 426 feet and could have tied the game, but the extra turf was just enough room for A's center fielder Sam Fuld to make a nice play

• Luis Valbuena also hit a 2017-adjusted home run in both 2015 and 2016, although both of his long balls barely made the cut at 400 ft and 401 ft, respectively
• The only other player to hit more than one 2017-adjusted home run over the last two seasons was Marwin Gonzalez, and they all came in 2016. Marwin hit a whopping 4 deep drives to center field that all ended up being loud outs due to the ballpark dimensions last year. His shortest went 405 ft and his longest traveled 424 ft.
• A.J. Reed had a 408 ft drive to center field last year that ended up being nothing but a loud out. To make matters worse, it could have been the difference in the 8/7/16 game against the Rangers that lasted 11 innings (and you can guess the outcome)

Let's hope the Astros continue to hit more fly balls to centerfield in the 400-426 foot range as those drives go from loud outs in 2015-2016 to game-changers in 2017. Go ‘Stros!!