"Durability trumps ability." That is a quote attributed to former Viking head coach Bud Grant. He was talking about football, but it applies elsewhere. And not just to sports. There are plenty of managers who have expressed frustration with an employee who is a good worker when there, but often not there.
In fact, as the Twins discovered this year, the better someone is at their job, the more difficulties they create when absent. The more they contribute, the more you have to spend to have someone else who has the skills to do their job available when they aren't there.
For the Twins, that's the situation now with Joe Mauer. They are going to have to find a backup catcher they are comfortable with as a starter if Mauer is hurt. That means you have a relatively valuable asset sitting on the bench when Mauer is playing. If the Twins didn't have Morneau at first, it might make more sense to think of Mauer as the second catcher and go find someone who is going to start 120 games.
In addition, Mauer is not just the Twins catcher, he is also the Twins number three hitter. With Delmon Young gone, the Twins don't really have any good alternatives with the potential to take the three spot in the lineup when Mauer is hurt either.
I am not one of the folks who is critical of Mauer. But the Twins need to think through the question of whether they can rely on him to fill his current roles. That is not just a question of a better backup catcher. It means finding an alternate starting catcher and an alternate number three hitter. They don't have to be the same person, but they need both.
Morneau and Span, in addition to Mauer, have durability issues going into next year. Those are probably the Twins three best players. Span can be replaced in center field by Revere, but Revere did not look ready to be a leadoff hitter on a championship team. Morneau can be replaced at first by Mauer or someone else. But the Twins do not have anyone else who is a legitimate cleanup hitter.
In short, the Twins need to look at next year and ask themselves whether durability trumps ability. If they build a team around Span, Mauer and Morneau, they may find they came up with the wrong answer. But worse would be a decision to straddle the issue. Unless they address the backup issues for leadoff, number three and cleanup hitters, they aren't going to win with better backups at catcher, first base and in the outfield.