The news that Barry Zito has been called up to start against Tim Hudson, with Mark Mulder in attendance, has rightfully thrown the baseball world into a mini-frenzy. Jonah Keri covered the meat of it spectacularly here. Here’s a dirty secret though: as we evaluate pitchers today, they weren’t great pitchers. An even dirtier secret: I don’t think it matters.

Zito, Hudson, and Mulder were undoubtedly good pitchers, racking up a Cy Young trophy and four more top-10 finishes in their time in Oakland. But were they great pitchers? Let’s take a look at their FIP- during their Oakland careers:

At their peak, they were well above-average pitchers, but, combined, they only had two top-10 finishes in FIP-, with Mulder finishing 10th in 2001 and Hudson 10th in 2004. Good, but not transcendent. If that’s worse than you remember, it’s probably because their ERAs consistently undershot their FIPs:

The Big Three were among the last players before sabermetrics exploded in popularity with casual fans, and our analysis of them reflects that. If they had come up today, would we label them as three guys who are above-average, rather than the cultural phenomenon they became? It’s very likely. That the cultural relevance of the Big Three has carried into the sabermetric era is a delightful reminder of how recently we crossed the frontier.

Does the fact that their accomplishments don’t hold up as well in the FIP era diminish their place in baseball history? I say no. Even though baseball has seen a number of better three-man rotations, the “Big Three” label feels at home in Oakland. In 2008, Dan Haren, Brandon Webb, and Randy Johnson, averaged a 76 FIP- for the Diamondbacks, better than any year of the real Big Three. But would Dan Haren starting against Brandon Webb on Saturday be a headline event (forgetting about the medical miracle required)? I doubt it. Zito, Hudson, and Mulder evoke something in us beyond their raw performance.

I always recited the order as Zito, Hudson, Mulder. Zito always comes first because as a fellow lefty who didn’t throw very hard, but thought he had a big hook, I emulated him both in real life and in MVP baseball, where I spent countless hours dropping his curve in against hapless computer foes. Zito was my guy and Hudson and Mulder fell in line after. Everyone had their own order relative to their personal biases. The combination of youth, talent, and personality made them relatable in a way that other greater pitchers just weren’t.

The Big Three were also the rock on which Moneyball was built. For fans of small-market teams, they represented what was possible. If your team scouted, drafted, and developed well, you too could have your own set of homegrown stars. The 2001 A’s-Yankees ALDS was, in my opinion, the pinnacle of the era. Zito, Hudson, and Mulder combined to throw 28.2 innings and give up just five earned runs, but it wasn’t enough. The 2001 A’s were one of the most likable teams of all time and the Big Three were the dominant reason why.

Although they had their best years in Oakland, when they were forced to move on, there was a sense when that they were headed for greater things. The potential they left behind in Oakland still tantalizes. Although the greatness never materialized in their new homes, it still feels like they left something on the table when they left. We never had the closure of seeing them grow old and decline together which is why finally getting our closure on Saturday feels so comforting.

You will note that Keri’s article does not once mention FIP. It’s a defensible choice because that’s not how we evaluated them at the time so it’s not how we remember them now. None of the reasons why we loved them are because they were the very best pitchers in the game or sabermetric darlings. It was a confluence of harder-to-quantify factors.

Baseball is a funny game. None of the Big Three ever had a season as good as Jake Arrieta’s this season. But ask me who I’m going to remember in 20, 30, 40 years? No contest. Baseball is an analytical nostalgia factory, a game that runs on both numbers and feelings without ever feeling like it contradicts itself. Perhaps no one represents that dichotomy better than the legendary Big Three.

I’ve always been fascinated by the outlier season where a guy puts up numbers well above or below his career pattern (Mark Reynolds’ 2009 steals total is one of my favorite examples). I wanted to take a look at the biggest outlier seasons in baseball history. To do this, I ran the data on every player-season since 1950 and calculated a z-score for each season based on the player’s career mean and standard deviation for that stat (only including qualified seasons). While the results were interesting, in my first pass through I did not control for age and the results were largely what you would expect – lots of guys at the beginning or ends of their careers.

On my second pass, I rather arbitrarily restricted the age to 25-32 to attempt to get guys in the middles of their careers. I think these results ended up being pretty interesting. The full list is here, but I’ll highlight a few below:

I had never heard of Bert Campaneris, but it turns out he was a pretty good player who put up 45 career WAR, mostly as a speedy, light-hitting, great-fielding shortstop. But in 1970, he briefly turned into a power hitter. He hit 22 home runs, his only season in double digits. He hit two in 1969 and five in 1971, playing full seasons both years. So this wasn’t even a mini-plateau. This was a ridiculous peak that he would never come close to again. We don’t have the batted ball data to dig further, but I would love to know just what was going on that year.

Dawson, on the other hand, was a pretty good home run hitter who usually hit 20-30 a season, except in 1987 when he blasted 49. Usually guys hitting crazy amounts of home runs in the late 80s through the 90s wouldn’t be that interesting, but these guys played for a long time after, never coming close to their 1987 totals again.

The guys on the downside are all fantastic home run hitters. With guys playing a full season and falling this short of their numbers, it’s always a possibility that they were playing hurt. Schmidt did indeed play hurt in ’78, but a quick Google for Thomas and Carter brought up nothing, making it all the more inexplicable.

As I mentioned above, in 2009 Mark Reynolds went 44 HR/24 steals. That was Reynolds’ only season stealing more than 11, but it “only” registered a z-score of 2.0. The three guys listed here blow that out of the water. Zeile had his season early in his career so it could have been a case of a guy losing speed or getting caught too many times and then being told to stay put. But Palmeiro and Yaz did it right in the middle of their careers. Palmeiro’s stolen base record consists of usually stealing 3-7, and getting caught 3-5 times. But in 1993, he decided to steal 22 while only getting caught 3 times. The next year he was back to his plodding ways.

On the negative side, Crawford’s struggles have been well documented. Driven by a .289 OBP and possibly declining health, Crawford’s 18 steals in his dismal 2011 season were the lowest amount of his career in a qualified season by far. We knew it was a shocking performance at the time, but I didn’t fully grasp its historical significance.

The last things I will look at are plate discipline numbers. They differ from home runs and steals because they represent hundreds of interactions, thousands if you consider individual pitches, rather than the dozens that the former two represent.

Mantle’s 1957 season deserves some attention (although he put up 11.4 WAR so it probably gets plenty of attention). That year, he put up the second best walk rate and the best strikeout rate of his career, at age 25. After that he went right back to being the great player he was before, albeit with slightly worse plate discipline stats.

Except for Money who was a guy early in his career working his way into better walk rates, this is something I don’t have a great explanation for so I’d love to hear theories. Why did Ripken in 1988, right in the middle of his career, take a bunch of walks and then never do it again to that degree? Likewise, how was Brett Butler able to cut his strikeout rate from 8.7% to 6.3% in 1985 then jump back up to 8-10% for the rest of his career?

Before I corrected for age, I got a bunch of results of guys at the tail end of their careers doing what you would expect. I do want to highlight one of them, however. In 1971 at age 40, Willie Mays had a 3.7z walk rate and a 3.1z strikeout rate. He walked a ton, but also struck out a ton. Added with his 18 home runs, that season he had a robust 47% three true outcome percentage. As the z scores show, it was a radical shift from anything he had done in his career and impressively, he used this new approach to put up a 157 wRC+ and 5.9 WAR. Apparently that guy was pretty good.

This piece identifies the biggest outlier seasons in history, but is crucially missing the why. And unfortunately, for most of these that’s not something I have a great answer for. If you have enough player-seasons, you’re going to expect some 3z outcomes. But historical oddities are one of the joys of baseball and each of the 3z outcomes is the product of a radical departure in underlying performance. I think it would be fascinating to talk to some of these guys and see what they have to say about why things went so differently for one season.

At age 35, Albert Pujols is having somewhat of a resurgent season. Many wrote him off last year after he posted his second straight, for him, subpar season. This year, though, he has hit 30 home runs through 108 games with ZiPS projecting him to get to 40 on the season. But there remain two big differences between 2015 and prime Pujols. One, he is walking less, at 7.5% vs. his career average of 11.8%. And two, his BABIP is a minuscule .228, continuing a declining trend:

It certainly makes sense that with a loss of footspeed, BABIP would decline as well. After doing a quick mental recall, I decided to look up Mo Vaughn as another power hitter who seemingly lost it overnight. And sure enough, he experienced a big BABIP decline late in his career as well:

He still put up a .314 BABIP in his last full season, but it was a step change from the average .365 (!!!) BABIP he put up from 25-30.

So, is this a larger trend that we should be paying attention to? Or are Pujols and Vaughn just confirmation bias. Thanks to FanGraphs’ excellently downloadable data, I expanded the datatset to include every season and every player. Grouping by age reveals:

Well seemingly a lot of nothing. The BABIP for all 20 year olds in that time was .301, while the BABIP for all 39 year olds was .295. Definitely a decline, but with a p-value of 0.7 is not statistically significant. So that’s disappointing for my thesis, but encouraging for all the old folks out there! Back to the drawing board.

Pujols and Vaughn were big, hulking guys. Maybe when they lost a step, it was a step that they could less afford to lose and the impact on their BABIP of a marginal slowing down was magnified. So what if we restrict the group to only power hitters? For this, I defined power hitters as players with career ISOs over .200. The results appear to support my hypothesis better:

This is plotted on the same scale as the previous chart so we can appreciate the relative differences. For this sample, the BABIP for power hitters declined from .313 at age 22 to .296 at age 36. Interestingly enough, power hitters had higher BABIPs earlier in their careers than the general population (including the power hitters), which then dip lower than the general population later in their careers. Apparently hitting the ball hard does have some benefits.

This time, the science backs up the hypothesis! My engineering professors would be so proud. With a p-value of 0.0165, the difference in BABIP between a 36 year old power hitter and a 22 year old power hitter is statistically significant. Pujols and Vaughn were indeed the victims of a real trend.

There could be a number of factors behind this. The first one I highlighted is the loss of footspeed. Second, it could just be that as you get older you don’t hit the ball as hard. Looking at exit velocity or ISO by age would help us judge that. Finally, age and a loss of bat speed or reflexes could lead to a change in batted ball in a way that leads to less balls falling for hits. It would make sense that as his bat speed slowed, Pujols tried to hit more fly balls to recover some of the home run power. That is the next thing I will look at.