They do run zone blocking but the Titans kind of have a bastardized version of it. The Titans are able to setup blocks to get Henry one on one versus defenders that have little chance of bringing him down. Whereas normally things are setup for a back that can explode through a hole and get downfield quickly.Titans run a zone blocking scheme very similar to Shanahan's. Plus I think Henry is good enough to shine in multiple offensive schemes. He might be better in some then others, but think he's still going to be a problem on 3rd and 2 regarless of the system.
Henry is a great back but he's not explosive, and I don't see us being able to give him the running lanes that a guy like him needs to get up a head of steam. Plus with the passing capability of this team I'd rather a back that cam complement that, rather than a two down back.