So far, Kelly has received far more minutes (19.8 mpg) than Sully (13.0 mpg), and more of KO's time on the floor has been with the top-of-the-rotation players, while Sully has logged a large share of his minutes as the veteran chaperone with a lot of the youngsters.
We have only played through three pre-season games, of which two were not even against NBA teams.
It is silly to read too much into what has happened so far.
While Sully has not seen the floor as much yet, he has not, actually, played all that badly in the minutes he has been given. Here are their per-36 comparisons (team rank in parenthesis):
Player PTS REB AST STL BLK
Sully 22.1( 5th) 11.1(2nd) 2.8(10th) 2.8(2nd) 0.9( 7th)
Kelly 13.3(12th) 6.7(7th) 4.2( 9th) 1.8(9th) 0.0(12th)
Viewed on a per-minute basis, it's not as if KO has out-produced Sully. Quite the opposite, in fact.
I think it's reasonable to observe that KO has been much more highly utilized and may so far look like a more obvious fit with the types of lineups that Stevens has put on the floor.
But I also know that this is just preseason and it is still very early.