The Titans don't trust Rusty Smith. I am not real sure why they even re-signed him to the practice squad after cutting him before the season- but that is neither here nor there.
What is here or there is the fact that the Titans have signed John Skelton today. Skelton worked out for them when Jake Locker hurt his hip but was ultimately signed by the San Francisco 49ers. They cut him after a couple of weeks. My guess is that he will be the backup by the time the Titans head to Indianapolis to take on the Colts in two weeks.
To make room on the roster for Skelton, the Titans sent Tommie Campbell to injured reserve. This move, presumably, will not keep them from trying to make Campbell the starter again next training camp.