I watched all of Sanborn's run snaps last year, because of course I have nothing better to do, and I feel even better about signing the guy. He's very average physically so he's never going to be a true playmaker or elite difference maker, but he's kind of the perfect steady role player who you can count on to be in the right position, hustle his ass off, and play with physicality.
The best way that I can put it is that if you put his brain into Murray's body you'd have a HOF player, because Murray has elite physical tools but kind of lacks the instincts and consistent physicality, while Sanborn lacks the elite athleticism but sees the game well and is always willing to physically take on blocks without hesitation.
He's not even that bad in coverage either, you don't want him to ever really be in a man situation because of the lack of top athleticism, but he's more than capable in zone and I saw two plays against the Vikings and Bears where he got pass deflections about 15-20 yards downfield. And of course we're going to be playing zone about 90% of the time, so there's no real concern with him being asked to play man.
I could easily see him being an Anthony Hitchens type player, very steady and consistent, not much of a difference maker, but you can throw him out there for 40 snaps a game without feeling like he's going to fuck you.