I'm going to take the unpopular side of GT on this one.
Riak is a great passer. Maybe the best-passing player over 6' 10" in Zips history. He sees the floor unbelievably well for a big. But Groce needs to empower the kid to score.
Riak gets a rebound 2 feet from the rim, and he's looking to kick it out for one of our 28% marksman to clang another three-ball. Just freaking dunk the ball. You're going up against MAC centers who'll be lucky warm the bench in the Holland Pro League one day. Dominate!!
If you can't dunk, just give a head fake and go up for the shot. You'll get fouled and go to the line, where you're actually a pretty decent free throw shooter.
I think Riak has the tools to be WAY better than what he's shown statistically thus far. He just needs to amp up his offensive aggression big time. Quit waiting for everyone else to carry the offensive load, and start throwing a few down yourself.