Catcher Aging Curves in the Mainstream

Travis Sawchick of the Pittsburgh Tribune-Review is one of the more analytically oriented mainstream baseball writers you’ll find, so perhaps it shouldn’t come as a huge surprise that he penned a terrific piece looking at the Pirates upcoming decision on Russell Martin. Included in that piece is this quote from GM Neil Huntington:

“We’re in an interesting era for age curves because of the skew of performance-enhancing drugs,” Huntington said. “We are trying to re-evaluate aging curves because they were taken way out of whack because of the influence of performance-enhancing drugs.”

Jeff Zimmerman noted a similar change in aging curves last year, showing that, since the 2006 season, offensive production has followed a continuous negative slope, rather than the traditional improve-peak-decline curve of the past. Given that the effects of PEDs on energy, stamina, and fitness are more clearly proven than the effects on hitting a curveball or recognizing a pitch out of the hand, perhaps we shouldn’t be too surprised that veteran players may have gotten a disproportionate advantage from the use of PEDs.

As Huntington notes, if the traditional aging curve models that were developed during the PED era no longer apply, this has some pretty significant ramifications for teams chasing free agents, especially at a position as physically demanding as the catcher spot. Last winter, I noted that the idea that catchers fall off a cliff in their early-30s was mostly a myth, but that data was based on a 30 year sample that included the heart of the “Steroid Era”, and it’s possible that using the substances that allowed catchers to play well into their mid-30s have been diminished in MLB.

As a sidebar in the piece, Sawchick included this graph:

Screen Shot 2014-10-28 at 11.20.59 AM

Certainly, it seems clear that productive older catchers were far more prevalent in in the 1990-2004 period than they were before or since, but it is interesting to note how much flatter the curve is in both the supposed non-PED time periods are. In both samples, the curve actually slopes up from 32 to 33, in fact, though this is likely just an artifact of having a small number of players in the samples. Still, the relative production from 32-35 is pretty stable, and as others have shown, framing skills seem mostly immune to aging. So, while the downturn in aging curves might be bad news for a 32 year old catcher, Martin’s own skillset might be one that ages better than others.

Martin’s going to be one of the most fascinating free agents of the winter. How teams handle their own internal aging curve forecasts might very well determine where he signs.

Dave is the Managing Editor of FanGraphs.

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Pirates Hurdles
Pirates Hurdles

This will indeed be fascinating. I think its assumed that Russ won’t get paid like a 4-5 win player that has been the last 2 years (without adding his framing runs), but where he ends up is very interesting. I have been floating 4 years $60 million for months, we shall see.