"By him not playing he allows Youk to bat which he wouldn't if Ortiz was playing."
If he was a better fielder than Youk he would be playing 1st & Youks would be DHing.
If you are arguing who is a better fielder between Ortiz & Giambi the answer is ...they both suck. They would be the two worst fielding 1st baseman in baseball. Fortunately...they are both very good/great hitters. Their best postion is AB