I think olynyk at worse can avg 7 rb in the nba.
Based on what? Kelly averaged 7.3 rebounds per game in college, playing in a conference where a lot of teams are lucky to have a guy who is 6'8".
Rebounding is one of those things that translates well between college and the NBA. If you are a mediocre rebounder in college, than you will be in the NBA.
I think Kelly will be right in line with Bargnani on the boards.
I don't think Olynyk projects to be as bad as Bargnani, mostly because Il Mago is historically bad.
Here are the worst rebounders 6'9" or taller last year, by rp36:
Steve Novak
Corey Brewer
Bargnani (4.6)
Chris Copeland
Tayshaun Prince
Matt Bonner
Jeff Green (5.1)
Chandler Parsons
Marvin Williams
Danilo Gallinari
Now, you are right Chris that KO averaged only 7.3 rebounds in college, but he played only 26mpg, and his rebound rate of 16.5% rates out as mediocre but not terrible.
I did some checking and looked for guys recently who averaged similar rates and are now in the pros. The comparable guys include Patrick Patterson, Andrew Nicholson, Meyers Leonard, Marcus Morris and others.
These guys are fairy bad rebounders at the NBA level - most are in the 50-60 range out of 70+ qualifying power forwards last year. Most average around 6-7 rebounds per 36 minutes.
If you want to find guys at lesser schools, it looked to me like some other guys with similar rates were Ekpe Udoh, Greg Smith, and Festus Ezeli (depending on what you think of the SEC). Udoh had very bad rebounding numbers last year, while Smith and Ezeli were actually pretty good.
Now, I'm not sure Olynyk will be playing inside like those other guys. But even so, I don't see him being quite as awful as Bargnani.
Now as to triboy's claim about >7rpg: even if you project Olynyk to be a rebounder on the same level as Meyers Leonard, he'd have to play a lot of minutes (32+) to hit 7 per game.
If he rebounds more like Brandon Bass, and plays 20 minutes per game, that would give him around 4rpg.