Rescheduling the Rolling Stones‘ postponed dates is turning out to be a bit tougher than expected. The band, which was forced to move the shows due to Mick Jagger‘s heart valve replacement surgery, had hoped to be able to re-book the concerts for this summer, but according to an inside source — that’s easier said than done.

Videomuzic.eu quoted an insider who said, “It’s proving a headache to fit these gigs in. There are only certain stadiums that can be used and availability is a problem. These tours take a long to time to get locked in. The fact is that Mick will be better in two months, but that doesn’t mean that’s when the tour will be. It’s much more complicated than that.12 NFL stadiums were part of the original tour. The NFL preseason starts in early August, which leaves a much shorter window to reschedule dates before running into football season.”

In addition to that, several of the stadiums have natural grass fields, which may preclude the stadium from allowing the field to be disturbed for the games.

While Jagger recuperates he’ll reportedly be taking medication to prevent blood clots, and will be unable to able to drive or operate heavy machinery for the first month. It could take as long as 10 weeks for Jagger to regain to his full pre-surgery workout stamina.