People will try to make this big news, but I imagine this is just to update the files in case something happens to one of the Titans' running backs. They've got to be happy with their three running backs right now. We all know how good Chris Johnson will be if he gets going, Javon Ringer is getting a chance to show what he can really do, and rookie Jamie Harper was a star in preseason.
Clinton Portis just turned 30 years old, the magic age where running backs have been known to dramatically decline in production. Portis has played only 13 games in the last two seasons due to injuries. He rushed for a career-low 227 yards last season before being cut in February.
Right now, through two games the Titans have the third least rushing yards in the NFL, but once Chris Johnson gets back to full speed, that should hopefully change. What's scary is that the Titans have the seventh most passing yards right now. This has a chance to be a top five offense if CJ gets going.