From a 2016 Dolphins article right after they signed Anthony Fasano and before Sims became Bear property:
And among tight ends, Fasano was graded the No. 1 run blocker by PFF. Dion Sims was rated No. 41.
No. 41!
Six million dollars a year for No. 41.
I recognize some have issues with ProFootballFocus metrics and I understand the skepticism. But when 40 spots separate one player grade from the next, you cannot argue the one is better than the other in the area we’re focused on -- run blocking.
https://www.miamiherald.com/sports/spt-columns-blogs/armando-salguero/article137677108.html
From the Dolphins fans I've talked to,
Sims seemed a lot like Kellen Davis. He looked the part, his size made you assume that he was a good run blocker, but he wasn't very good at anything. JMO. I would say that Sims' performance in Chicago substantiated that thought.