Sproson says it's no coincidence that Vale have yet to concede a goal with the 6ft 5in on-loan Crystal Palace defender in the side.
He told The Sentinel: "Ryan Inniss is something completely different to what we have had in the last couple of years.
"He's an out-and-out centre-back who wants to defend and go and win the ball in the air.
"We have had defenders who are comfortable on the ball and can play out from the back, but they have struggled when they have come up against teams with a physical presence up front.
"Inniss is a rock and he will go and win that ball. He is a Ryan Shawcross type player.
"Having said that, I don't think he is the finished article and I am sure he would acknowledge that."