actually, putting Duncan on Dirk is probably the worst thing they could do. Dirk is too good of a shooter to leave open in order to guard the inside. and if Duncan played up on him, it will leave the middle wide open for lots of easy baskets by Howard, Harris, Daniels, and Stack... all of whom love to drive and cut inside. Dirk is also faster than Duncan, and would be able to drive past him, and draw some double and triple teams, leaving someone open. If they put Duncan on Dirk, it will be a short series for the Spurs.