How A Move to First Base Would Affect Miguel Cabrera’s Defensive Value


Oct 17, 2013; Detroit, MI, USA; Detroit Tigers third baseman Miguel Cabrera (24) reacts during a pitching change during the seventh inning in game five of the American League Championship Series baseball game against the Boston Red Sox at Comerica Park. Mandatory Credit: Rick Osentoski-USA TODAY Sports

Miguel Cabrera won his second straight MVP award earlier this month, but the baseballing world was sharply divided as to whether or not he was the player most deserving of the award. Cabrera was certainly the best batter in all of baseball last season, but his all-around game (or lack thereof) calls into question whether or not he was the best (or most valuable) player in the major leagues.

Featured prominently among the counter arguments – which are centered around WAR calculations – is always the defensive component. Cabrera was nearly 17 runs worse than the average third baseman last year according to UZR (18 runs worse according to defensive runs saved). Single season data samples of defensive metrics are notoriously noisy, but pretty much everyone agrees that Cabrera is below average at the position (and likely among the worst) due to his relative lack of mobility and range (even though he was quite good at other aspects of the position such as arm strength and throwing accuracy).

The question is, then, will Cabrera’s individual WAR calculations improve if he’s playing a position at which he has at least a chance to be average?

Probably not, actually.

In his first four years as a member of the Detroit Tigers, Cabrera spent most of the time at first base (all but the first few games). During that time he averaged a seasonal UZR of -2.2 runs at the position. That’s slightly below average, but very nearly average. In his last two seasons at third base, he’s averaged -13.3 runs at the position. One might think that the difference there – 11.1 runs or basically 1.1 WAR – could/would be added to Miguel’s total, but a little thing called ‘positional adjustment’ is going to cloud the calculus.

Because defensive metrics (like UZR) are scaled so that zero is the average for that position, an adjustment is made to account for the fact that it’s easier to be average at first base than it is at third base than it is shortstop. Shortstops can shift to third base when they lose range, center fielders can move to a corner outfield spot, and old catchers with bad knees can just stand at first base. There’s a sort of continuum, and this is applied to WAR calculations to better approximate the individual value of a player.

During his 2008-2011 stretch as a Tigers first baseman, Cabrera’s defense (UZR) plus positional adjustment came out to an average of -14.8 runs. That is, compared to every other MLB player at every other position, Cabrera’s defensive contributions were estimated to be about 15 runs less than the average guy (it’s almost impossible even for a very good first baseman to be above average in an absolute sense). In his two years at third base, his average defense (UZR) plus positional adjustment came out to -11.5 runs. That three-run differential isn’t enough to make a big impact on WAR, but this all shows that the move from third to first does nothing to improve Cabrera’s value as a player (unless it also improves his durability or longevity).

So next year when we’re (again) having the same WAR debate, the argument won’t be so much that “Cabrera is a horrible defender” as it will be “first basemen just don’t have much defensive value”. The finals WAR totals will be much the same, but defensively we’ll be comparing his totals to a different positional peer group.