I'm not expecting a Superman-like leap, but I do expect to see him improve on last season. Keep in mind that Rabb was only a freshman last year so 2nd team PAC-12 is an accomplishment. He averaged 12.5 and 8.6 while posting 12 double-doubles. He's a throwback big with a well developed post game. When he gets the ball in the post he is very decisive going to the hoop and can finish through contact. Rabb only shot 67% from the free throw line but is I think he will be up around 72-75% this season. On defense he plays smart and keeps his hands up. He can be disruptive on the defensive side of the ball and posted 10 games with multiple blocks.
Rabb had to share the rock with four other good to very good players last season and all five averaged at least 10 points. Of that group only Rabb and Jabari Bird(10.4 ppg) are returning this season so there will be more opportunities to score this season. I could see Rabb averaging something like 17 ppg, 11 rpg, and 2 bpg. They aren't otherworldly numbers, but looking at all the other big guys the options are limited and I think Rabb could be the best big man in college this season.