Jaguars' Defense

I have some concerns with Jaguars' defense.  The starters are 23rd in total defense in the National Football League.  Now, I understand its only the preseason, but the Jaguars must be able to stop the run consistently throughout the regular season if they're to dethrone the Colts in the AFC South.  With signing of rookie standout, Derrick Harvey, the Jags should improve their pass rush, therefore, with the Jags' pro bowl caliber corners interceptions should rise.  What do think about the 2008 Jacksonville Jaguars?