Salter has good wrestling and good technique. Salter has never been a great athlete and at his age what he had is fading. I do think he'll be a great coach because he lacks that athleticism so he makes up for it with game knowledge. But as a fighter, he's not very strong. Of course he's stronger than me, but compared to the other MWs in the division he's not as physically powerful as Mousasi, or particularly Lovato Jr, or Tokov, Vanderford, etc. And he's obviously not explosive. If he doesn't get knocked out quickly, I think he will probably take Mousasi down at some point. But he won't be able to do much more than lay on him. And Mousasi probably won't get the sub either, without rocking him first. But even if he lays on him, 10 seconds, 20 seconds, 30 seconds, Mousasi is stronger and unlike Van Steenis has good technique, so he will be able to stand up. And then Salter will have to take him down again, which will further deplete his gas tank, and Salter at his age and with his skill has a declining gas tank. So Salter will probably take him down a couple times, Mousasi will get back up, and then Salter will be tired and drop his hands and Mousasi will drop him. I don't really see any way Salter could win.
Vanderford is basically developing into a better Salter. He doesn't quite yet have the same jiu jitsu pool of knowledge but he's catching up. They're the same size but he's better in every way, faster, more explosive, stronger, better cardio. At a certain point Salter's body can't catch up to what his mind wants to do, if they were to fight tomorrow I'd pick Vanderford over Salter, even though he still has a little bit more to learn about jiu jitsu.
