This conversation belongs to about three years ago. Since then, teams have found ways to isolate and expose pure shot blockers (rim protectors, if you prefer that) by playing 3-point shooters at the 4 and 5 positions. Think back to last year's finals, when the Warriors put Bogut on the bench and started Draymond Green at center, something they've done a lot more of this year. It essentially negated the usefulness of Mozgov.
The question shouldn't be "Where is our rim protector going to come from?" It should be "Where are we gonna find a guy who can block shots, switch onto smaller players in the pick and roll, handle the ball, shoot from the outside, and rebound?" In other words: "Where are we gonna find a player like Draymond Green?"
This is why players like Olynyk should get every opportunity to grow and develop. Olynyk can shoot, handle the ball, pass, defend most 5s, switch on the pick and roll (though you wish he were a bit more nimble). He "protects the rim" according to advanced statistics, even though he doesn't have long arms and block a lot of shots.
Similarly, this is what you *could* have in Mickey, once he's a finished product: A guy who blocks shots at a really high clip, switches onto smaller players on defense, rebounds, and shoots the 3. That's an immensely valuable and very rare collection of skills in today's NBA. Let's see if he can put it all together.
The league has changed. Pure shot blockers (er, rim protectors) who don't do other stuff are not as valuable as they used to be.