Nary a day goes by in the baseball world does a day pass without two people discussing which of their favorite players was better than the other. Our daily baseball ritual includes this process, especially now during the Hot Stove season. We start with a gut reaction, a quick thought that we post on a forum or we Tweet it. Then we have that moment of panic…”What if that statement was way off base?” So, to make sure we’re not wrong, we whip open new tabs to accommodate Baseball Reference, Fan Graphs, or various pitch f/x sites. We come to our conclusion and either back off the statement, try to pretend no one saw it, or, hopefully, rub the fact that we were so right in the faces of other commenters or our followers. We do this same song and dance when it comes time to debate the Hall of Fame credentials of one player over another or when two similar players retire at or around the same time. For this article, as you can tell from the title, we’re going to be doing the latter, featuring Mike Mussina and Andy Pettitte.

Mussina started his career (1991) four years earlier than Pettitte (1995), but their careers overlap greatly. What helps is that they faced essentially similar competition since both of them were in the A.L. East for the duration of their careers (minus Pettitte’s three year stint in Houston). This is something that makes comparing them much easier. But why now? Well, the easy answer is that Pettitte just retired and Mussina retired after 2008. They’re both fan favorite pitchers who happened to be very good at throwing a baseball and getting batters to make outs because of it. The other reason? Someone from East Coast Sports Fans forwarded Moshe the debate as it was unfolding and asked our opinion on the matter. Moshe asked me to write it up, so here it goes…

Both pitchers were paragons of durability. Mussina pitched a remarkable 18 years in Major League Baseball while Pettitte racked up a similarly long career, pitching in 16 big league seasons. Both pitchers had just one year in which they threw under 100 innings–Mussina’s debut in 1991 in which he threw 87.2 innings and Pettitte’s 2004 in which he threw 83 innings. Per 162 games, each pitcher averaged over 200 innings: 215 for Pettitte and 226 for Mussina. We’re dealing with two pitchers who were healthy and effective for many years.

Sticking with our per 162 games average, let’s take a look at two of my favorite pitchers side by side:

Mussina: 34 G, 226 IP, 219 H, 99 R, 92 ER, 24 HR, 50 BB, 178 SO, 1.192 WHIP, 8.7 H/9, 0.9 HR/9, 2.0 BB/9, 7.1 K/9, 3.58 K/BB, 3.68 ERA, 123 ERA+, 3.57 FIP.

Pettitte: 34 G, 215 IP, 224 H, 103 R, 93 ER, 18 HR, 68 BB, 158 SO, 1.357 WHIP, 9.4 H/9, 0.8 HR/9, 2.8 BB/9, 6.6 K/9, 2.34 K/BB, 3.88 ERA, 117 ERA+, 3.75 FIP.

Oh my word. Are there two pitchers more evenly matched than Pettitte and Mussina? Their ERA and FIP differences are minuscule and Mussina’s edge in ERA+ is just six points. He has a slight edge everywhere else, except Pettitte did a better job of keeping the ball in the park…but just barely. The biggest advantages we see are Moose’s respective edges in WHIP, strikeouts, and K/BB. Let’s see if we can dig a little deeper and get anything out of this.

Here’s their batting lines against:

Mussina: .255/.297/.399/.696
Pettitte: .270/.326/.398/.724

We see the gap grow in Moose’s favor a bit here, but that stems from his slightly lower BB/9. Pettitte does have the lower SLGA, which is a result of his slightly lower HR/9. For the sake of context, the 2010 AL average OPS was .734.

We’re coming up with advantage Mussina over and over again here, but let’s see if there’s something else we can do. This is something that we discuss a lot when we talk about MVP voting: peak vs. longevity. We’ve essentially already covered longevity. Both had very long careers and Mussina’s got a slight edge in just about everything. But, consider this a final not on longevity and effectiveness.

The one thing every fan, writer, and analyst alike said when reminiscing about Andy Pettitte over the last few days was his incredible consistency. Only once did Andy end a season with an ERA+ under 100: 2008 when he finished with an ERA+ of 98. Mussina had three such seasons towards the end of his career: 98 in 2004; 96 in 2005; and 88 in 2007. This is definitely something that could start to tip the balance back towards Andy; he had fewer seasons of below average pitching. But, of course, that’s only one side of the coin. Let’s look at peak/career bests and see what we come up with.

Pettitte’s high in ERA+ was 177 in 2005. Mussina never beat that; his career high was 164 in 1994. Pettitte’s peak, though, is hard to nail down because of his consistency. He never had any wild dips and climbs in his ERA+ numbers. Moose’s peak is a little easier to nail down. 1994-2001 were the best years of his career and in that stretch he had a 132 ERA+. Because of how level Pettitte’s career was, it’s almost as if the whole career was a long, extended, even plateau. When we set a different bar, perhaps seasons of 120 ERA+ or higher, we could see something different. Pettitte cleared this rather arbitrary bar four times. Mussina cleared it 12 times. In terms of staying above league average, we saw Pettitte beating Mussina there. However, in terms of exceeding a higher level of performance, Mussina gets the easy win.

Andy Pettitte’s career was so consistent (yes this word has been used a lot but there’s no getting around it) that there wasn’t a period of extended dominance and it didn’t feature a lot of great years. Mussina had more of a decline at the end than Pettitte did, but Mussina made up for that with many more better-than-just-good years than Pettitte. What’s another way we can flesh this out? Let’s look at everyone’s favorite vaguely controversial stat: WAR.

In terms of fWAR, based in FIP, Andy Pettitte racked up 66.9 WAR. Mussina tallied 85.6 WAR. That’s an 18.7 fWAR advantage in Mussina’s favor. Shifting to bWAR, based on RA, Pettitte managed 50.2 bWAR, or 3.9 per 162 games. Mussina was worth 74.8 bWAR, or 5.2 per 162 games. These advantages for Mussina aren’t huge, but they’re not insignificant. If we hearken back to our ERA+ examination from before, we see similar results. Mussina never reached Pettitte’s career high in bWAR (7.6), but Pettitte cleared 5.0 bWAR just three times, while Mussina racked up 5.0 bWAR or more seven times. fWAR gives a repeat: Mussina never reached Pettitte’s best (7.4), but he cleared the 5.0+ fWAR more times (11) than Pettitte (4). We’re seeing the pendulum swing toward Mr. Moose here.

Part of the query Moshe received was a look at the big-game performances, the playoffs. Long ago, I looked at Andy in the Playoffs, so I’ll just rehash it here: despite some great playoff performances with some stinkers in there, Andy’s playoff numbers look exactly like a normal regular Andy Pettitte season.

Mike Mussina had “only” 139.2 innings pitched in the playoffs, compared to Andy’s 263. And, surprise, they look a lot like one of his regular seasons. He had a 3.42 ERA, a 1.103 WHIP, and a 2.1 BB/9. He gave up a few more homers than normal (1.2 HR/9) but also struck out more guys (9.3 K/9) and had a better K/BB (4.39) in the postseason. On raw numbers in the playoffs, like in the regular season, Mike Mussina’s got an edge over Andy Pettitte. Pettitte gets more credit for being a playoff performer because he played for five World Series winning teams, whereas Mussina never got that elusive ring. That doesn’t mean, though, that Mussina was a worse playoff performer because of it.

Running through this exercise was more than enjoyable. If I had to pick today, Andy Pettitte and Mike Mussina would be my two favorite pitchers ever, and easily my favorite pitchers I’ve seen in pinstripes. Looking back on their wonderful careers and letting my memory jog was a treat. Now that I’ve come to the end, I have to decide on which pitcher was better. I’m tempted to stay sitting on the fence, refusing to choose between a favorite righty and a favorite lefty, but as Mr. Colbert would say “Choose a side; we’re at war!” My side? Mike Mussina. His regular season numbers were better, even if just slightly, and the same goes for his playoff numbers. Over the course of each player’s wonderful and wonderfully long career, Mussina was worth more by both WAR systems, and had more impressive individual seasons than Pettitte did (even if Pettitte didn’t have as big a decline and was the definition of consistency for 16 years). You’re all smart enough to know this, but I’m saying it anyway: this decision, in no way, means I think Andy Pettitte wasn’t a great pitcher for a long time. He certainly was and there’s little debate about this. The only thing I’m saying is that Mike Mussina was a better pitcher than Andy Pettitte. The list of pitchers who weren’t as good as Mike Mussina is definitely a long list and there is no shame in being on it, especially if you’ve had a career like Andy Pettitte had.