Do pitchers actually perform better approaching free agency?

“And of course, he’ll be a free agent at the end of the season, so he’ll have extra motivation to perform well.”

How many times have you heard that on a broadcast about a player on the cusp of free agency? The popular theory that a “contract year,” that is, the last year of a player’s deal before becoming a free agent, has a non-insignificant affect on performance is one as old as free agency itself.

Most recently, the contract year theory has been applied to try to understand the successes of Michael Pineda or the struggles of Masahiro Tanaka. Both pitchers are expected to hit free agency after the 2017 season, Pineda for the first time and Tanaka after exercising an opt-out clause in his contract. Believers of the theory will claim that Pineda is pitching better to impress potential suitors, or Tanaka is pitching worse because the pressures of free agency are “getting to him.”

There has been a little bit of research on the contract year phenomenon in the NBA, which found that while individual scoring numbers tended to improve, ancillary performance (rebounds, shooting percentage, etc) remained in line, roughly, with the player’s career average. In this spirit, I thought I’d test the theory on the previous two free agency classes.

For this test, I looked at pitchers who had thrown at least 20 innings in their contract year. This was to avoid “reclamation” projects or journeymen pitchers who don’t have enough career innings to sustain a small sample size swing.

I further took the last two years of pitching free agents, as this gives a sample size of 234 pitchers. The last two free agent classes have been opposites in terms of pitching depth, with the 2015-2016 class featuring names like David Price, Zack Greinke and Johnny Cueto. Conversely, this year’s class was much thinner in terms of pitching talent. Again, using two opposite seasons should cancel out market factors beyond performance, like bidding wars.

Finally, I filtered out any retiring players, since there’s no “incentive” for them to perform better.

What we’re looking at is simple: do pitchers perform better in their contract year than they perform over their career averages? To test, I plotted the correlations between the contract year ERA (which we’ll call ERA₁) and career ERA, contract year FIP (FIP₁) and career FIP, and contract year fWAR (fWAR₁) and the fWAR a pitcher in this set averages per season.

What you would expect to see, if you believe in the contract year theory, is points settling on equivalent spots on their respective axes, or lower on the x-axis than the y-axis. This would indicate that a pitcher had a stronger year - or at least, an equal year - in their contract year than their career average.

Instead, what you get are a series of roughly randomized clusters. Closer inspection reveals something of particular interest however.

It turns out, pitchers actually slightly underperform their career performance in contract seasons, though not egregiously.

2016 pitchers saw their ERAs rise 0.88, FIP rise 0.629 and fWAR drop .41. In 2015, contract year pitchers experienced a 0.49 increase in ERA, 0.50 rise in FIP and a loss of 0.2 fWAR vs. their annual averages. Overall, contract year pitchers ERA’s are 0.64 higher, their FIP is 0.629 higher, and they drop about .281. That’s right, a contract year pitcher tends to be about a quarter of a win less valuable, at least using this two year history.

Now, this is by no means a predictive analysis. I cannot use this data to tell you how Tanaka or Pineda will do over the remainder of the season.

What this tells us, simply, is that the contract year theory doesn’t really exist. There’s no data to suggest that pitchers are extra motivated, and so pitch better. The numbers also don’t support the other side of the contract year theory either. Pitchers do tend to underperform their averages, but not by such an extreme amount that you can attribute a contract year phenomenon. It wouldn’t attract your attention to see your favorite pitcher’s ERA rise by just over half a run in one season, and so you shouldn’t attribute that kind of difference to something like the contract year theory.

What’s affecting Tanaka, and what’s boosting Pineda, is tangible and measurable. You can find their problems and successes in analyzing their command, or pitch selection, or maybe even which catcher they’re throwing to. The answer to their seasons is out there, but it’s certainly not the effects of a contract year.