There has been a lot written about the St. Louis Cardinals offenses of 2010-2012 under Mark McGwire, due to it's greatness. There has been a lot written about the St. Louis Cardinals offenses of 2013-2015 under John Mabry - perhaps more than McGwire's - due to it's ever changing nature. Many people believe it has gotten worse. Has it?

Bernie Miklasz was tweeting last night about the incredible pitching this season and how the hitting has not kept up, leading to an unfortunate record over the past 25 (I believe) games. After receiving what seemed to be 2 tweets questioning if it's time to look for a new hitting coach, Bernie tweeted again. This time it said: "And here comes the whining over Mabry. The big revelation? Cards had more power with McGwire as batting coach 2010-2012 ..."

Being someone who loves to find out answers to things - statistically - I dove in.

First off, here are the team offenses (not including pitchers) for each season - and compared to league average - remembering that 2015 is incomplete:

under McGwire

2010 - .271/.341/.416/.757 - .332 wOBA - 106 wRC+ (10th in league, 5th in NL)

2011 - .281/.350/.439/.789 - .344 wOBA - 119 wRC+ (1st in league and NL)

2012 - .280/.347/.435/.782 - .339 wOBA - 114 wRC+ (T-1st in league, 1st in NL)

under Mabry

2013 - .278/.342/.416/.758 - .332 wOBA - 112 wRC+ (3rd in league, 1st in NL)

2014 - .259/.327/.380/.707 - .315 wOBA - 101 wRC+ (14th in league, 7th in NL)

2015* - .261/.329/.400/.729 - .317 wOBA - 103 wRC+ (11th in league, 5th in NL)

* - so far

It is easy to see that the St. Louis Cardinals offenses were better under McGwire, finishing first in the league two out of three seasons and finishing top third the other season. Under Mabry, they looked like McGwire's offense for the first year, then have since fallen into the middle third of the league. That is not in question. Those are facts.

What is in question here is if the power drop by the team is due to Mabry's coaching or if it's due to personnel. I don't know that we'll be able to get a definitive answer, but let's look at some more facts.

Under McGwire, the Cardinals had the following players with at least 500 plate appearances in 3 seasons (ranked from highest wRC+ to lowest):

Lance Berkman

Albert Pujols

Matt Holliday*

Allen Craig*

David Freese*

Carlos Beltran*

Colby Rasmus

Yadier Molina*

Jon Jay*

Rafael Furcal - under 100

Skip Schumaker - under 100

Daniel Descalso* - under 100

The three bottom players are noted as being below a league average hitter. All of the rest ranged from Berkman's 158 wRC+ (58% better than league average) to Jon Jay's 115 wRC+ (15% better than league average).

Under Mabry, the Cardinals had the following players with at least 500 plate appearances in 3 seasons (ranked from highest wRC+ to lowest):

Matt Holliday*

Carlos Beltran*

Matt Carpenter

Jhonny Peralta

Matt Adams

Allen Craig*

Yadier Molina*

David Freese*

Jon Jay*

Kolten Wong - under 100 (holy crap, he's still under 100?)

Daniel Descalso* - under 100

Pete Kozma - under 100

Again, the three bottom players are noted as being below a league average hitter. All of the rest ranged from Holliday's 139 wRC+ (39% better than league average) to Jon Jay's 101 wRC+ (1% better than league average). As you can see, the bottom of the barrel guys are still there, but the top guys are not nearly as good hitters, despite some of them being the same players. The players that have traded out? McGwire had Berkman, Pujols, Rasmus, Furcal, and Schumaker. Furcal and Schumaker were under league average and in essence have been replaced by the also under league average Wong and Kozma. Funny, two middle infielders for two middle infielders. The three before that (Berkman, Pujols, and Rasmus) however, they provided some serious pop. They've been replaced by an OBP machine in Matt Carpenter, one of the best SS in baseball in Jhonny Peralta, and powerful but super under-performing Matt Adams.

The * next to certain players' names mean that they have at least 500 plate appearances under both McGwire's and Mabry'stenures as batting coach. Let's look more closely at those players. That is where I believe we can glean the most information. I know I've been using wOBA and wRC+ up to this point, because we've been discussing offense as a whole. However, when looking at these 7 players that are in common, let's look more closely at power, because Miklasz's tweet was specific there. One of the best statistics to use for determining power is the ISO statistic. It is simply the player's SLG minus the players AVG. (SLG-AVG) It ascertains how many extra bases per at bat the player takes, whether by double or triple or home run. While speed does come in to play on some of those triples, doubles, and inside the park home runs, the over the wall homers are the majority of what goes into the ISO.

ISOs under McGwire and Mabry, by player:

Beltran .227/.195

Holliday .216/.172
Craig .215/.128
Freese .150/.119
Yadi .143/.119
Jay .114/.080
Descalso .091/.108

As you can see, the transition from Mark McGwire to John Mabry as hitting coach has resulted in the following +/- by each player:

Beltran - minus 32 points ISO

Holliday - minus 44 points ISO

Craig - minus 87 points ISO

Freese - minus 31 points ISO

Yadi - minus 24 points ISO

Jay - minus 34 points ISO

Descalso - plus 17 points ISO

Notice, I did not say that Mabry caused this. I'm not trying to imply that Mabry caused this. I'm just pointing out the results of what happened. Remember, we are not looking at the Cardinals replacing Schumaker's bad bench bat with Kozma's worse bench bat here (for example). We're comparing individual players to themselves.

Let's look more closely at each player.

• Carlos Beltran played a year under each hitting coach. He was 35 and 36 years old when these seasons occurred. By most standard aging curves, he was well past his prime both seasons. That argument cannot be made here.

• Matt Holliday played all 3 years under each hitting coach. He was 30-32 years old when McGwire was here and 33-35 while Mabry's been here. He's an aging player and was in/closer to his prime under McGwire. Fair argument here.

• Allen Craig played his age 25-27 seasons under McGwire and his age 28 and 29 seasons under Mabry before being shipped out to Boston. He should have been in or near his prime during both tenures. That argument cannot be made here.

• David Freese played his age 27-29 seasons under McGwire and his age 30 season under Mabry before being shipped out to Anaheim. He was really playing injured for much of 2013 under Mabry. Fair argument here.

• Yadier Molina played his age 27-29 seasons under McGwire and his age 30-32 seasons under Mabry. He's an aging player and was more in his prime under McGwire. Fair argument here.

• Jon Jay played his age 25-27 seasons under McGwire and his age 28 and 29 seasons under Mabry. He should have been in or near his prime during both tenures. That argument cannot be made here.

• Daniel Descalso was quite bad either way...but improved his ISO under Mabry in his ages 26-27 seasons after playing for McGwire in his age 23-25 seasons. This makes sense as those were more prime-aged seasons.
  

Like I said, I don't think any myths have been debunked or any of that. I just think this shed some light on the issue. Perhaps it muddied the waters and made more questions than answers. I'm not certain.