I'm not sure that the Titans will have Chris Johnson's contract renegotiated by the time the preseason starts. In fact, I don't think they will. This leaves Javon Ringer as the heir apparent to the running back throne.
If Johnson is asking for more money than the Titans want to give him, I could see that affecting how the Titans play in the preseason in one of two ways.
One: the passing game becomes the focus of the offense, with runs as a secondary option. The Titans might try this to show Johnson that they can function as a team without him.
Two: the Titans coaching staff puts its faith in Javon Ringer and Jamie Harper and runs the ball anyway. I think this will be the option they choose, since it will give them a better look at who really needs who.
Even if Johnson's holdout lasts into the regular season, don't be alarmed. Half the rushing attack will still be there. Tennessee drafted Jamie Harper in the fourth round of the draft because he is big and powerful in the run.
Harper weighs in at 235 lbs and has a 40 time of 4.59 seconds. That isn't slow, especially for a running back his size. He was drafted to be Tennessee's third down back, and that won't change whether or not Johnson is there.
Whatever happens with Ringer, Harper and Johnson, Tennessee will have a good idea of what to expect from their rushers at the end of the preseason with or without CJ2K.