In my opinion, Olynyk is the one to trade.
Olynyk is one year older.
Sullinger started 44 games to get his per 36 numbers, against NBA starting centers, playing out of position much of the time.
Olynyk started 7 games, beating up on a lot of 2nd unit guys- as a starter I don't think he's anywhere near Sullinger's numbers vs starting quality NBA players.
Sullinger is higher risk overall because of his injury concerns, but as a basketball player he's much more complete. I'm not sure what Olynyk's role will be in the NBA. He's like Kevin Love but he can't rebound...that to me screams of someone like Spencer Hawes- a soft big man with long range but not much else. In fact I don't think Olynyk's inside game is anywhere near the level of Spencer Hawes, he relies on the stretch dribble-drive game like Nowitizki rather than the stretch inside-out game of Spencer Hawes.
People forget that Sullinger hasn't played two full seasons in the NBA AND he's younger than Olynyk. He still hasn't had a full off season to recover from his surgery or work out/ concentrate on his body. We saw one pic of Sullinger less than 2 weeks after the season had finished, and all of a sudden he's the local donut boy to all us internet GM's.
While they both have strong awareness on the court, to me, Sullinger's basketball instincts are better overall, and he's got an eye for the ball and an understanding of the game that not every player has. Olynyk is a smart kid, but his defensive confusion is almost embarrassing at times. That doesn't mean he won't work it out, but he's got such a long way to go that I don't see him being a two way player or a force inside against NBA starting units the way Sullinger is.
Sully needs to lose weight, and he needs to keep working on his jumpshot, but as he gets stronger, leaner and more experienced, he's got the potential to be an All Star on a David West/Carlos Boozer in Utah level.
I do like Olynyk and he's got potential, but I believe Sullinger is the better player.
I guess if we aren't keeping either for long, and we are getting Kevin Love, then we should ask ourselves:
After a Minnesota trade, which of Sully or Olynyk has more trade value around the NBA when we trade them to add more pieces to a Celtics tandem of Rondo and Love.
Perhaps Olynyk...
Personally I'd rather keep Sully. Just my opinion.