I like the ATH and DEF of both Brydon and Block better than Ardito.  But Ardito has great REB and LP which makes this a tough call.  Dont' worry about Block's 17 DUR. I can't  remember the last time I even looked at a DUR rating

I think I'd start Block at PF and Bryden at C. If their shooting percentages are atrocious, you can bench one of them for Ardito later.   However,   I could easily be talked out of this plan.

For defensive purposes, I'd agree with alblack. My only caveat would be to balance your scoring. I am starting to think that having 2 good scorers in each of your starting and backup units is a good idea. If you need Ardito's scoring to balance out your starting unit, I'd start him. With your m2m defense, you can try to hide Ardito against the lesser athlete of the 2 bigs you'll be playing from game to game, so he can be either a PF or C. I generally consider the PF and C to be interchangeable.

I haven't taken into consideration but what about this guy? He is a sim recruit but look pretty good so I haven't rescinded him yet.

http://wisjournal.com/hd/PlayerProfile/Ratings.aspx?tid=0&pid=2257350

If his REB were better, I'd be tempted to start Graves. 

Maybe let graves play some SF?

I KNOW IT WAS A ROOKIE QUESTION BECAUSE YOU POSTED IT LIKE THIS

also, I agree with alblack.