What caused the Oakland A’s collapse?

For much of the season, the Oakland A’s dominated not only the American League West, but really the league as a whole. At the All Star break, Oakland had the best record in baseball at 59-36, and though the Los Angeles Angels went on a tear and started closing in, there seemed to be little doubt in most people’s minds that the A’s would win the division. And if they didn’t it would be because the Angels of Anaheim continued to surge, as opposed to any kind of slump from Oakland.

If all that wasn’t enough, they were the poster-boys for the use of run differential, blowing every other team out of the water with a +145 mark, again with the Angels coming in behind them, at a distant +89.

They then chose to seal everyone else’s fate (or at least that is what it felt like), grabbing ace left-hander Jon Lester at the deadline, adding him to an already impressive staff that already included the likes of Sonny Gray, Scott Kazmir and early-July acquisition Jeff Samardzija. Combine that kind of pitching with hitters like Josh Donaldson and Brandon Moss, and a little bit of the magic fairy dust that seemingly always finds itself giving at least one or two A’s players the ability to play way over their head for no reason, and it seems like a forgone conclusion.

And that’s when everything went haywire. Despite the aforementioned acquisitions, run differential, and magic, the A’s have fallen off the earth. They managed just a lowly 12-17 record and -11 run differential in August, losing their division lead to the Angels. And while LA did have itself a strong month, it likely wouldn’t have mattered with Oakland playing .414 ball. That 12-17 record put them fourth in the division during the month, behind the Houston Astros, in addition to LA and Seattle.

Now, anyone can have a rough month, even as unlikely as it would seem to be for what was such a dominant team until that point. There can be unfortunately timed-slumps, bad luck, or any number of factors. Normally, those types of things don’t last long, and will start to even out.

In the case of the A’s, that doesn’t seem to be what is going on. They have continued their scuffle into September, going 3-7 as of writing this, despite a respectable +8 run differential over that time. That’s a combined 15-24 since August began, with the team looking like a shadow of its early-season self.

Before we get into dissecting why this may be happening, you may be wondering why I am bringing up run differential. To put it simply and obviously, teams that score more runs than they allow tend to win more games. We can use run differential as a check and balance to a team’s record, as more often than not, run differential holds some predictive value.

We can use the pythagorean expectation (runs scored^2/ runs scored^2 + runs allowed^2) to predict what a team’s record “should” be. As of August 1st, they had scored 535 runs and allowed just 374, for an expected winning percentage of .672 (their actual Win% was .611). Over 162 games, that would make for 108 wins and 54 losses. Now, that seems pretty extreme, and that’s because it probably is. The system is far from perfect.

But at the time, if I was going to predict the rest of the year for the A’s, I would probably be more likely to believe they would get even better than I would that they would fall off the face of the earth, as they have.

So why did it happen? If their actual performance, along with a quick yet trusted projection system, showed them to be a great team, why did the A’s start losing?

One theory is that they messed with the chemistry in the clubhouse. They traded an everyday player in Yoenis Cespedes, and brought in another new face. I personally find this to be pretty unlikely. Though there may be something to chemistry, losing one player and adding another doesn’t seem extreme enough to cause a team to go from dominant, to struggling. And in any event, things like chemistry are unquantifiable, so there isn’t much to gain from discussing them, at least in this form.

Instead, I chose to look at the numbers the team has put up since August 1st, compared to what they were able to do in the first half. Doing so gives you a pretty clear idea of why the team as a whole has hit this rough patch.

They posted a team wRC+ of 85 in August, 22nd in the league, and an even worse 74 wRC+ so far in September, which places them 24th in the league over that time. Clearly, neither of those outputs are conducive to winning, and they didn’t always have top-notch pitching to fall back on either. Their 3.71 ERA in August is about in the middle of the pack, though that mark has improved to 2.84 in September.

But that doesn’t really fill us in all that much either. Of course a team that holds a losing record is either hitting poorly, pitching poorly, or both. But why?

When we look at the individual performances of the players, we get a good idea of why the team as a whole has been losing. Josh Donaldson, Josh Reddick and Eric Sogard were the only regular players to have an above average (greater than 100) wRC+ in August. The team leaderboard then drops all the way to Sam Fuld’s 83 wRC+, and then to three players in the 70’s. It gets as bad as Alberto Callaspo’s 43 wRC+ in 98 plate appearances, and John Jaso’s 30 wRC+ in a platoon role (51 PA).

This is a team that, while having good/great players like Donaldson and Moss, relied on finding production from unusual places. They utilize platoons, have sufficient depth, and always seem to squeeze value out of otherwise unproductive players. That effect wasn’t there in August. If one player struggled, they weren’t able to plug in the next guy and not miss a beat. 1B/DH/C Stephen Vogt had a 76 wRC+, but the alternates for his role (Jaso and Derek Norris) were also well below average.

And that makes sense to a degree. Vogt was player over his head up to that point, and he was due for regression. Other players, despite having been proven commodities in the past, were bound to slump eventually. It just so happens that multiple players slumped all together, and probably the worst possible time. The Angels surged into 1st place, and the Mariners and Royals played well enough to get within 0.5 games of Oakland as of Saturday.

If I had to guess, I would expect the A’s to pick back up at some point. They probably aren’t as good as they were in the first half, but they also aren’t a sub-.500 team with only three above average hitters. Unfortunately for Oakland, much of the damage may have already been done. There are under 20 games left in the season, and they may not reignite in time to save their season.