Mark Eaton from the Jazz was listed at 7'4" 290lbs. He also had a 10+ years NBA career.
If Sim can trim down to about 310-320 lbs, he could be a player down the road. Watching his videos, he has some offensive talent and of course he is just a huge road block for anyone coming in the lane. If he can trim down and keep the weight down, he could eventually become a starter, playing 25 min a game. He would probably average at least 2-3 blocks per game on sheer size alone.