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Molina is to Pudge as Pudge is to Inge

John Dewan

Excerpted from The Fielding Bible - Volume II

Mike Mussina finished a brilliant pitching career with his first 20-win season in 2008 at the age of 39. On the Yankees roster with Mussina were two of the best catchers over the last 10+ years, Jorge Posada and Ivan (Pudge) Rodriguez. But it was a third catcher, who in eight previous seasons had never appeared in even half his team’s games, that caught 32 of Mussina’s 34 starts. Jose Molina was Mike Mussina’s personal caddy during the 2008 season. Molina also became the personal caddy for another superb veteran pitcher during the last two months of the year–Andy Pettitte.

Why do two of the best pitchers for over a decade prefer to pitch to Jose Molina behind the plate than two of baseball’s best catchers? The New York Daily News ran a story by John Harper about Mussina and Molina in early August after the Yankees trade for Pudge Rodriguez. Here’s Harper’s take on the trade:

“It’s nothing against Ivan Rodriguez. The Yankees could have traded for Johnny Bench in his prime and Mike Mussina would have said, ‘That’s nice, but I’ll keep Molina.’”

Earlier, in July, Mussina shared this about Molina with Tyler Kepner of the New York Times:

“Calling a game, catching the game, throwing the ball, blocking balls, being a leader on the field—he’s a No. 1 catcher,” Mussina said. “He knows how I think now. He’s important. He’s real important.”

On July 31st, Andy Pettitte had a horrible outing with Ivan Rodriguez behind the plate, giving up 11 hits and 9 earned runs in 5 1/3 innings. According to the New York Journal News, Pettitte asked to no longer throw to Pudge and asked for Molina to become his personal catcher

Molina caught all ten of Pettitte’s final ten starts.

Catcher ERA and Earned Runs Saved

So Mussina and Pettitte both like Molina better, better than one of the best defensive catchers of all time, Pudge Rodriguez, and better than one of the best overall catchers of the last decade, Jorge Posada. But do the numbers back them up?

Now, before we look at the numbers, I want to throw out a caveat. Whether the numbers do or do not back Mussina/Pettitte up, we have to take them with a grain of salt. Over the course of a season a full-time starting pitcher in this era won’t get more than 30 to 35 starts, and 35 is rare. That’s a small sample size. And when you start breaking down the data into smaller groupings (i.e. so many starts with catcher A, this many with catcher B, and a couple more with catcher C) the sample size becomes an even greater problem. Sample size is always something to consider. If a hitter gets eight hits in 20 atbats, no one truly believes he is a .400 hitter. But if he goes 80 for 200, people start to believe that there is something special about the guy. Having said this, it’s worth looking at the data and interpreting it with this in mind.

OK, enough with the stat lesson. Here’s the data for Mussina and Pettitte by catcher in 2008.

Mike Mussina
Catcher G GS Inn ER ERA
Jose Molina 32 32 190.1 68 3.22
All Others 2 2 10.0 7 6.30
The Others:
Jorge Posada 1 1 7.0 2 2.57
Chad Moeller 1 1 3.0 5 15.00
Ivan Rodriguez 0 0 0 0 ---
Total 34 34 200.1 75 3.37

Andy Pettitte
Catcher G GS Inn ER ERA
Jose Molina 18 18 112.2 52 4.15
All Others 15 15 91.1 51 5.03
The Others:
Jorge Posada 8 8 46.1 28 5.44
Chad Moeller 6 6 39.2 14 3.18
Ivan Rodriguez 1 1 5.1 9 15.19
Total 33 33 204.0 103 4.54

Some observations:
• Pettitte’s bad outing with Pudge was the only outing with Pudge.
• Pettitte has his best ERA with Moeller catching, but only six outings.
• Both Mussina and Pettitte had better overall ERAs with Molina catching, although Molina only missed two starts with Mussina.

The data does back up Mussina and Pettitte. They both wanted Molina and they both pitched better with him. In Mussina’s case, the better indicator is not the ERA in the two starts without Molina, but the fact that he had a tremendous season at age 39 with Molina catching nearly all his games.

But again, the sample size is small. Let’s add in the other key Yankee pitchers with Molina catching.

Molina catching Yankee pitchers
Pitcher G GS Inn ER ERA Pitcher Overall ERA
Mike Mussina 32 32 190.1 68 3.22 3.37
Andy Pettitte 18 18 112.2 52 4.15 4.54
Chien-Ming Wang 8 8 55.1 23 3.74 4.07
Joba Chamberlain 23 5 47.1 12 2.28 2.60
Mariano Rivera 35 0 39.1 5 1.14 1.40
Jose Veras 35 0 35.0 9 2.31 3.59
Kyle Farnsworth 31 0 30.2 10 2.93 4.48

Every pitcher who threw 30 or more innings to Jose Molina for the Yankees in 2008 had a better ERA with Molina than they did overall. If you sum these amounts for all Yankee pitchers, you find that the pitchers had a collective 3.69 ERA with Molina catching. That’s Molina’s Catcher ERA; we’ve been keeping this stat for many years now. The Yankee pitching staff overall ERA was 4.28. Molina looks like he made a real difference.

We’re still working with a small sample size, but this is starting to build.

One reason Molina’s catcher ERA looks good is because he caught almost every game of the Yankees best pitcher, Mike Mussina. This artificially lowers Molina’s catcher ERA. But wait. We just said Molina made Mussina’s ERA better and now we’re saying Mussina made Molina’s ERA better. We could keep going round and round like this but there is a solution. It’s Earned Runs Saved.

Earned Runs Saved is a number that tells you how many earned runs the catcher saved for his pitcher. I’ll do Molina and Mussina as an example. If Molina caught every one of Mussina’s games, his earned runs saved would be zero because there’s no basis for comparison. But he didn’t and here’s how it works.

Mussina’s overall ERA was 3.37. If Mussina had a 3.37 ERA with Molina catching in the 190.1 innings he caught, Mussina would have allowed 71.3 runs. Instead, the Mussina-Molina combination only allowed 68 runs. That’s 3.3 runs saved. We round this off and simply count this as 3 runs saved.

This technique works better than comparing catcher ERA to staff ERA, or even comparing one catcher’s catcher ERA to another, even on the same team.

For the complete article, check out The Fielding Bible-Volume II.