Phenoms and Age

For unto everyone that hath shall be given, and he shall have abundance. But from him that hath not shall be taken away even that which he hath.

This morning I read Tom Verducci's underwhelming article on the Angel's 20-year-old superstar Mike Trout and immediately began thinking about his future. He's good now. Check. He's going to presumably be great in the future. Check. But I got thinking about something else:

How will he age?

I'm sure Trout will put up tons of production in his career; hell, he's 20% of the way to my HoF benchmark of 50 WAR. I wondered, though, about what constitutes a 'phenom' and what repercussions this might have on a player's physical aging process.

I thought about this quite a bit during Harper-mania in the last few years. This isn't a fantasy novel. Harper is not a special player because of some innate, magical gift. He was so ahead of his age curve because he developed early. He was a full-grown man at 15 or 16 years of age.

In the fantastic book Outliers, Malcolm Gladwell talks about hockey players, and one point he makes is that NHL players are more likely to be born in the first few months of the year. When these players were children, they were ahead of their peers (if only by weeks or months) physically, which made them (on average, and by a small amount) bigger and stronger and better. They therefore got more playing time and subsequently more development.

Early physical development is everything. It's what allows those hockey players to be better, and more importantly, it's what allows men like Harper and Trout to dominate their age peers and compete with their age superiors, and makes them what we now refer to as 'phenoms.'

But here is my thought process: If these guys develop faster, does this mean that they will age faster as well?

So, I took the good old Tango age curve and went to Fangraphs to identify 38 players who had accumulated 5+ WAR by age 21, players that clearly showed prodigious ability at an early age. Here's what I found.

The normal age curve has players peaking around age 24-28, with a value progression that looks like this (1.00 is peak value and all others are the portion of that peak value):

20 - 0.71
21 - 0.84
22 - 0.89
23 - 0.95
24 - 0.97
25 - 0.99
26 - 1.00
27 - 1.00
28 - 0.97
29 - 0.95
30 - 0.93
31 - 0.90
32 - 0.88
33 - 0.84
34 - 0.79
35 - 0.74
36 - 0.69
37 - 0.64
38 - 0.57
39 - 0.52

What you see here is a relatively quick hop to their peak in their early-mid-20s, a sustained prime until about age 29, then a gradual decline which starts to really drop off in the early-mid-30s.

My thinking was that if 'phenoms' begin their development earlier than everybody else, maybe the processes that constitute a physical decline (erosion of physical structure, abilities, reflexes) would begin earlier, as they had, in essence, been an adult for longer than their peers. Here is the age progression I got:

20 - 0.65
21 - 0.86
22 - 0.91
23 - 0.89
24 - 0.98
25 - 0.95
26 - 1.00
27 - 0.93
28 - 0.84
29 - 0.82
30 - 0.67
31 - 0.75
32 - 0.67
33 - 0.61
34 - 0.42
35 - 0.47
36 - 0.35
37 - 0.40
38 - 0.46
39 - 0.30
40 - 0.18

Of course, the data jumps around a little bit due to the sample size, but the trend is pretty clear. These phenoms peak around the same age as normal players - age 24-26. However, there is a nearly immediate decline. The change from age 26 to age 27 is noticeable and and they are in clear decline by age 30. By age 34 these players were a shadow of themselves, producing less than half the value that they once did. 

These 39 phenoms began their decline much earlier than the norm, and it was significantly more steep.

This is not to say that they were all washed up by age 32. Remember that these were largely legends of the game; Ted Williams, Mickey Mantle, and Hank Aaron were all in this data set. The average annual WAR did not drop below average (2.0) until age 39. These guys played outstanding baseball late into their careers, but that is not the point. Their personal declines occurred very differently than the norm. Regard:

This exercise reminds me of a couple of immediate case studies: The last two phenoms of our current generation: Ken Griffey, Jr and Alex Rodriguez, both of whom were included in the aforementioned data set. Both were in the majors as teenagers, both All-Stars at 20, both MVPs by 27, and both began to see their bodies break down in different degrees shortly after their 30th birthday. These are two guys out of tens of thousands of MLB players, and we can't rule out external factors, but still, it bears thinking about.

Now, because of the fact that phenoms represent generational talents, and therefore usually come to be world-class players, the resonance of this information is somewhat diminished. The best player in the world has regressed to become top-5? Oh no. Take, for instance, the recent few editions of Albert Pujols. Sure, he's not what he was in 2009, but he's still an exceptional player, and as a result there isn't as much concern about him.

One area where this makes me think is in the doling out of super-contracts, like the ones that A-Rod signed, or the ones that Harper and Trout will sign. Teams should be aware (and likely are) that just because they are signing the league's best player at 27, an age where most players are half a decade from seeing serious declines kick in, that guy might not follow the usual rules. Phenoms are not 'most players.'

So is Mike Trout a great player? Yes. The best player in the sport? He might very well be. And should he have a great career and maybe end up in the Hall of Fame or even go down in Mays/Mantle status, or even higher than that? Yes, yes. But, if, at an age that he has no business doing so, Mike Trout, or Bryce Harper, or Manny Machado stops playing like a deity and begins to traverse the far side of that mountain of talent, don't say I didn't warn you.