The definitive, maybe, sort of prediction about Joe Mauer’s future

A comment in the earlier post about Joe Mauer moved me to pull out a spreadsheet I haven’t touched since 2003 today. It’s a spreadsheet I created consisting of calculations from baseball statistics guru Bill James, which he used to predict the future performance of players.

BROCK2, as he called it, considered the performance of a player, the age at which he turned in the performance, and how the performance compared to other players at the same position, among other things.

I found it to be a very accurate gauge although I think the last time I used it, it predicted Manny Ramirez would end his career with over 700 homers. BROCK2 doesn’t properly take drug use and goofiness into consideration.

The way the spreadsheet works is as you enter historical statistics for a player, it spits out a prediction for subsequent seasons.

After entering Mauer’s first three seasons, the spreadsheet predicted his performance this year would consist of a .347 batting average , 18 HR and 88 RBI while playing 155 games. Not too shabby.

The more data the spreadsheet has to work with, the more refined the predictions get. After entering his fourth season’s data — 2007 — the numbers didn’t change much in predicting this year, lowering his HR total only slightly. After entering 2008’s stats — a year in which he played 146 games — the production prediction continued to drop, though not precipitously.

2009’s statistics, once entered, doubled nearly all of the projections for the future. That was Mauer’s big season, of course. The spreadsheet said Mauer would hit 27 HR and bat .327 this year. It also predicted that the season Mauer would have in 2010, would be pretty much the season he had, except that it expected about 5-10 more HR.

And after entering last year’s statistics, going into this year, it said Mauer would bat .333 and hit 27 homers, and that his career would end with about 238 homers, although he’d play into his 40s.

What does the addition of this year’s statistics do? Since the season isn’t over, I pro-rated his performance so far over a full season, adding 18 percent (the amount of the season left) to his line.


That’s not horrible. But it’s not superstar, either. Curiously, if Mauer moved to first and his production remained roughly the same, his career would end sooner. More offense is expected from a firstbaseman.

If you’re a baseball stats freak who’d like to play with the spreadsheet — for a long time, as far I know, this was the only spreadsheet available using James’ formula — drop me an e-mail and I’ll send you a copy.

For all I know, this formula has been proven folly by now. I’m not as stat-freaky as I was in my hang-on-every-pitch youth. But here’s a write-up analyzing James’ method of evaluation.

One more note: The last time I used this on a Minnesota Twin was at the height of Lew Ford-mania. It predicted Lew’s career was about over. It was.

  • `Jim Shapiro

    Following baseball statistics – more than those from any other sport that I’m aware of -can be a game in and of itself.

    (For example, BA with a 3-2 count on natural grass played outdoors in a city east of the Mississippi with a high unemployment rate but a low crime rate on a Wednesday at 3:17 pm in August during a leap year when the temperature is 73 degrees F and the wind is blowing in from left field at more than 7 mph and the pitcher is Jewish but seriously considering converting to Islam if his fiance’s brothers strongly suggest it.)

    But in the end, as in most things involving human behavior, past is prologue.

    Unless it isn’t.

  • frightwig

    If Mauer meets those projections through age 35, while remaining the team’s primary Catcher, I think the Twins could live with it. Of course those lines are nothing like 2009, and he’d probably be overpaid to some extent, but at those levels I’d guess that he’d be worth ~5 WAR in each of the next three years and 3+ WAR for at least a few years after that. He’d still be among the better Catchers in the game.

    I just hope that his knee holds up that long, or that a move to a corner spot in a few years might add some life to his offensive production after his peak seasons have passed.