Saturday, January 12, 2008

Tough Catchers?

A few years ago I was reading some baseball book that argued a certain catcher from the very early part of the 20th century should be included in the Hall of Fame because, among other things, they played in a large number of games when catchers generally didn't hold up that well over a season. The names, perhaps, aren't that important, but I wondered how true it was that catchers have progressively played in more games over time. It makes sense this might be true because of the improvement in protective equipment and general fitness.

Of course, to actually see a change in catchers' ability to play through a whole season, it's necessary to make the playing field fair, as it were. Obviously a starting catcher today will have a chance to play in more games even before the season starts since much of the 20th century was played with eight (or more) fewer games per season per team. Thus after finding the average games played (detailed below), I adjusted it to a 162-game season by dividing that average by the average number of games played per team (total league games divided by number of teams) and multiplying by 162.

So, how then did I find the average games played by catchers? First, taking everyone who played as a catcher obviously will skew the numbers. I wasn't that interested in seeing how, say, the third-string catchers throughout the league did. Instead, I wanted to focus on starting catchers since they have the greatest opportunity to play in many games and teams usually have an incentive to keep them in the lineup (one extreme: dropping off from Johnny Bench to Bill Plummer is no fun). In order to try and grab these starting catchers from teams without having to look up every team every year, I decided to search for games played by catchers sorted from greatest to least and take the top eight (or ten, or twelve, etc.) from there based on how many teams played in each league that season. I then combined the lists to find the MLB average (and, for what it's worth, I even remembered to include the Federal League at the last minute!). Finally, I wasn't all that interested in players like Jimmie Foxx in 1935 or 1940 - sure, he played in 147 and 144 games in each season, respectively, but the bulk of that time was at first base. To make sure I got only full-time catchers and, in an attempt to avoid part-time DH's), I looked only at players who appeared in 80% or more of their games at catcher. It's kind of arbitrary and I may have missed someone who played in a lot of games but only 78% of them as a catcher, but I doubt there were many cases of that. Each season had a lot of high numbers of games played by catchers, so I would guess most starting catchers made it on to my list somehow.

There's bound to be some errors in this; I didn't take the time to rigorously search every team to see who their starter was or to verify they didn't use their catchers as pinch-hitters very much. In any event, this should show the general trend of playing time for catchers since the AL started in 1901.

Here is the AL starting catchers chart:

(click to enlarge in a new window)

There's an interesting jump in games starting in the mid-1910's and a slight dip in the 1940's before the average stabilizes around 115. Note the dark black lines in each of these charts are a moving average for the previous 10 seasons. The blue line is the number of games played for the catcher in the league who spent the most time in the lineup.

Take a gander at the NL chart:

(click to enlarge in a new window)

The NL has seen less jumping around than the AL over the years. There was a slight bump in the 1930's, but not really to the degree the AL saw in the 1910's and 1920's. Otherwise, there was a steady increase of in games played until leveling off between 115-120 games per year.

Finally, here is the chart for both leagues (and, for 1914 and 1915, the Federal League):

(click to enlarge in a new window)

The bump in each league can be seen in the late 1910's and 1930's. The 1970's and early 1980's saw a slight increase before scaling back to the same level the average has been at since the 1950's. I think it's fair to say catchers play more now than they did in the early part of the 20th century, but that early part doesn't last as long as I figured it did. Looking at the MLB chart, the 10-season average was near the present-day level as early as 1925.

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