DallasBasketball.com's Mike Fisher asked coach Don Nelson a few questions on the minds of Mavs fans and got some answers.  Here are the answers, in brief:
(1) Bradley's playing time is erratic because he is very useful against true centers, but not very useful against forwards playing center.
(2) Howard was benched because he can come in as a center or a power forward and "direct the action."  Nelson also said he's glad Howard could accept his new role.
(3) Nowitzki is playing power forward to better utilize his strengths.  When Finley and either Buckner or Griffin are on the floor, the defense is forced to put a power forward on Nowitzki who can use his footspeed and outside game to his advantage.  If a small forward covers him, Nowitzki is forced into a post-up situation where he can be double-teamed.
(4) Tim Hardaway is important to have because Steve Nash is (in Nelson's words) "slight."  He is liable to get injured if he plays a lot of minutes.