Well, the rich get richer and the poor get poorer –- the Minnesota Twins have inked Joe Mauer to a massive eight-year, $184 million contract extension. Wait, what? The Twins aren’t rich? Could’ve fooled me.

What this means is that, more likely than not, Mauer will be playing baseball through at least 2018, when he is 35 years old. Mauer still has one season left on his old contract before the extension kicks in. (Nothing is guaranteed, but at $23 million a season, it would likely take a career-ending injury for him to not be playing baseball in some capacity through the entire contract.) But how much longer will Mauer be wearing the tools of ignorance?

To figure this out, I took a look at all the players who met the following criteria:

  • Made their debut in 1974 or later
  • Have finished their careers
  • Lasted for at least five years in the majors
  • Started out as a primary catcher (more than half their games played at catcher in seasons they were eligible for Rookie of the Year)

 There were 203 players who met all four criteria. On average, they tended to be a full-time catcher for about 10 years. And on average, their careers lasted about 11 years. It turns out that for most catchers, there isn’t much life after catching.

We do know, though, that Mauer isn’t a typical catcher. His bat can play anywhere on the diamond. So let’s examine the players in this group who did have a career after catching (23 of them in all). They played an average of 12 years in the majors, and seven at catcher.

Mauer has already been in the majors for six years, and as we discussed previously, is very likely to play for at least nine more seasons. So we fully expect him to outlast the average as far as total career length. Given that, it wouldn’t be outrageous to see him beat the average as far as career length as a catcher, either. Especially since Mauer is younger than the average player in the sample. He made his debut at age 21, compared to an average age of 23.

And the Twins are probably not in a big hurry to move him. They have Justin Morneau locked up at first base at least through 2013. Since the Twins are probably not excited about the idea of their $200-million man learning to play third base or the outfield at this point in his career, that leaves the only other option as designated hitter.

This research is based on averages, of course, and isn’t destiny by any stretch. But the odds are that Mauer won't be able to remain a full-time catcher much more than halfway through this contract, so by then the Twins better have a contingency plan in place.