There is something to be said for choosing the bat over defense.
If you take the absolute best defensive team in baseball, and compare it to the absolute worst defensive team in baseball, I think you will be surprised to find that the worst team with allow about 80-90 more baserunners over the ENTIRE season than the best team. That means just over one extra baserunner every couple of games.
I have not done the math on the 2011 season yet, but was extremely surprised when I did the math on the 2000-2010 seasons.
So, would you accept one extra baserunner every two games in order to have Alonso's bat in the line-up full-time?