Here is our first cut at the concept...a "backup catcher" is one who receives more than 150 plate appearances but less than 300 plate appearances and whose plate appearance-to-game ratio is less than three per game. Some teams utilize their regular catcher enough to prevent the "backup" from qualifying by this definition: at some point later on we'll measure that phenomenon, though we suspect that such usage has become increasingly more common as we get closer to the present day.
What we want to know here is how many catchers have had at least three seasons which qualify according to the above set of conditions. That total: 194.
Additional seasons, as you might expect, prove to be a good bit more scarce: only 111 catchers have four or more seasons that meet the criteria; 54 have five or more seasons; 32 have six or more; 14 have seven or more; just 5 have eight or more.
|Little did anyone know back in 1969 that Buck|
Martinez would become the most prolific
backup catcher in baseball history...
The "king" of backup catchers by this definition is Buck Martinez, with ten such seasons. One gets the impression that Buck's gift for gab, which has manifested itself in a series of different gigs in his post-playing days, may have also contributed to his curious longevity as a marginal player. Amazingly, Buck never had a season where he had more than 300 plate appearances--meaning that he was never, ever considered worthy of the starting job.
Most of the catchers at the top of this list have come from more recent times--you will recognize names such as Jose Molina, Paul Bako, Doug Mirabelli, and Junior Ortiz. Most of these fellas were just as light with the bat as Buck (only Mirabelli's lifetime OPS+ is above 80). Most of these guys simply couldn't hit enough to hold their jobs, but they had some other skill that kept them around--something that might not be especially quantifiable.
The other trend here is an odd one in a baseball world that is (if you believe the rhetoric, that is) increasingly dominated by economic determinism. As the chart below shows, the efflorescence of the "backup catcher" began in the 1910s (at a point when platooning first became popular). Our measure here is the number of backup catcher seasons per team as calculated by averages over decades (1900-09, 1910-19, 1920-29, .... 2000-09, 2010-12).
We see some fluctuation (a big drop in the 30s, possibly tied to a series of big-hitting catchers), but the average of "backup catchers per team" stays high through the 60s, and then begins its decline. That average is now at its lowest since the first decade of the twentieth century.
But at the same time, there are more recent catchers hanging on in this capacity, and at higher numbers of seasons. With baseball salaries being what they are, you'd think that teams would simply try out young catchers and rotate them; but we see a tendency to rely on the hard-to-quantify skill sets of a series of veteran players who clearly aren't earning their roster slot with their bats.
So, as you brave the gales of winter awaiting the clarion call of "pitchers and catchers" (coming not a moment too soon!), ask yourself: why is this so? What is the je ne sais quoi of these backup catchers? Is there some mystical commingling of experience, game calling, pitch framing, and defensive prowess that makes them into guys who miraculously overstay their welcome? Or is it just cheap labor operating under the radar of free agency? Sometimes it's the marginal things that illuminate the big picture--and sometimes those margins are carrying the dust of eons...