Note: I am “out” this week, preparing some stuff on the World Baseball Classic, that will appear on Aerys’s Around the Horn blog.  To fill in, I’ve asked… my fiance to write up a blog post for you.  Incidentally, he is known on the internet, anonymously and mysteriously, as ‘Mr. Tiger’. Because he is a Tigers fan. But he can introduce himself.

This guy would obviously have skewed the numbers a bit, back in the day.

Hi, I’m Mr. Tiger. You might remember me from such posts as “Let’s do this Neyer-style”, and “So, you’ve decided to Photoshop Mr. Redlegs’ head onto a daguerreotype baby”. So, how old are the Reds? They’re the oldest professional team, as long as you link the Red Stockings to the current incarnation. Which we obviously do around here. The Ol’ Left-hander, Joe Nuxhall, still holds the record for the youngest player to ever appear in a MLB game, coming in to get two outs (allowing 5 runs) in the middle of an 18-0 blowout.

So how old were the 2012 Reds? There are a few ways to define the age of a team, but I’m going to deal with three here:

1. The normal way – Sum of player ages divided by number of players.
2. Weighted by usage (e.g. G, PA, IP)
3. Weighted by value (e.g. WAR, wOBA)

Method 1 is straightforward but not very useful (okay, more not very useful), since Pedro Villarreal (1 IP) counts the same toward the average as Brandon Phillips (623 PA). The weighted values are also reasonably easy to compute. For example, the sum of the product Age*WAR divided by the sum of the WAR gives a WAR-weighted average.

For usage weighting, I’ve used PA, and made the assumption PA=IP*4 for pitchers. This is just to be able to lump hitters and pitchers into the same group for usage. For value weighting, I’ve used (FanGraphs) WAR. No assumptions are needed in order to combine hitters and pitchers for value.

The 2012 Reds were 28.0 years old by usage, and 27.4 years old by value. This is against league averages of 28.4 and 28.2 years respectively. Two things are interesting about these data. The usage and value weights are close, with younger players being a little more valuable than older players per plate appearance. The split is a bit larger for the Reds, but it’s by no means the largest split I came across. Looking at playoff teams, the Giants had the largest split of about a year and a half (28.3 vs. 26.8). Teams did make the playoffs being well “off-peak” in terms of age, as well: the oldest playoff team was the Yankees (31.6, 31.8), and the youngest was the Nationals, at (26.9, 25.8). Out of curiosity, I did look up the Astros, who came in at (25.9, 26.2), which was the youngest team by usage that I found.

The league split between value and usage, where young players are slightly more valuable than their use would suggest can probably be attributed to several things:

1. Managers trust veterans.
2. Slumping veterans will be given a longer look to ride out the slump.
3. Veterans that have gotten worse (not just slumping) will still be played because we’re paying them, dammit.

A slightly more detailed version of this analysis would probably be involve figuring out any patterns to the deployment of these older players in terms of regular/non-regular status. It should also be pointed out that none of this is probably quite as useful as a different measure of “age”, years left on contract weighted by value. Thank you for plowing through my tedium.

Tara: YAAAAY! Thanks, Mr. Tiger.