If It turns out that Gruden actually assisted in recruiting Petersen to Knoxville, it would keep Vol Nations love for Gruden strong without him taking the job himself. I could see Gruden liking that scenario.
Also, people need to remember that Petersen is no stranger to recruiting outside his own backyard. There arent a lot of 5 stars (or even 3 stars) in Idaho, and even at UW his best players were coming from Los Angeles, NorCal, and Hawaii. With the right people that know the territory of the Southeast (like Austin Thomas) I expect hed do just fine recruiting at Tennessee.