It is really a meaningless stat as 'payroll' is just a measure of how much signing bonus money has been included in a specific year to deal with 'cap' issues. Dead money is a big issue as it shows how much of that earlier bonus money is going out to players who have been cut. But since dead money is part of the salary cap caculation it is already being dealt with in the number every team has to remain below.
Any team that signs bigtime FAs or restructures big contracts or extends bigtime players is going to have a big 'payroll' number. I believe Brady's restructure to free cap space hit in last years payroll number which is why the pats were ranked so high. About 7M of Brady's cap hit this year and next will not show up in the Pats payroll number because it has already been accounted for last year so their payroll number will likely go down compared to other teams. With a 21M signing bonus to Brady hitting payroll last year you would expect the Pats number to be high. Likewise a team like Balt if they sign a contract with Flaco rather than tag him will likely have a huge payroll number next year as all of his signing bonus will hit the books in this coming year.