So A-Rod won the American League MVP. I think one of the most interesting issues in baseball, a sport so full of nuanced debates, is how to define "most valuable player."

Many observers contend, and I agree, that the most valuable player is not simply the best player. It can be the best player, but not because the player is simply the best. The most valuable player is the one that makes the biggest contribution to his team. It's the player without whom the team would have fared most worse.

And so by that definition, I don't agree that Alex Rodriguez, as good as he is, was the most valuable player this year. Instead I would have given it to Yankees relief pitcher Mariano Rivera. Yes, relief pitchers pitch a very small number of innings. But without Rivera's spectacular consistency throughout the entire season, the Yankees don't stand a chance of making the playoffs, much less competing for the division title.

Just as a reminder, Mariano's 2005 stats:
• 1.38 ERA in 78.1 innings over 71 games
• 43 saves
• 80 strikeouts
• 18 walks

It's not just his stats. If you get to Rivera, you win. If you don't, you lose. If that's not valuable, nothing is.