The Coors Factor: Does it REALLY make Colorado Rockies offense better?

Now we get to the interesting part. The part where we really get to test the whole idea of “Coors will make you a much better hitter!” and how accurate it truly is.

Here’s a list of players who we’re going to look at that joined the Rockies as Free Agents after having played quite a few seasons for other clubs (and who also got a decent amount of ABs with the Rockies):

• Jason Giambi
• Michael Cuddyer
• Gerardo Parra
• Justin Morneau
• Ian Desmond
• Daniel Descalso
• Mark Reynolds

If hitting at Coors would truly make hitters better then we should see their wRC+ increase. So, let’s take a look!

Now let’s take a look at the pre-Rockies and post-Rockies list for these players:

Now in this list only Cuddyer improved his wRC+ and that’s mostly because he had a career year in 2013 by posting a wRC+ of 138 (and he also had a crazy year in 2014 by posting a wRC+ of 150 but only in 49 games). Everyone else regressed, though, and not exactly by slim margins (besides Morneau, who stayed flat).

Part of their regression is going to be a natural trend that’s evident with Rockies free agent signings: They’re old and on the back-end of their careers where regression is expected. While that’s true, an increase in wRC+ should be a little more common that it is with Rockies free agent signings. And with only one player showing an increase, it helps prove our point that Rockies hitters DO NOT become better simply by making Coors their home field. The challenges that were pointed out before are new challenges that not every hitter can adapt to.

Now does Coors truly make a hitter better simply by them making it their home field? The data above shows that it absolutely does not.