Basically the team is saying Crawford is more valuable now than Griffen would be. Position flex and all that...
I think the Joneses want whomever starts at DE to not be perceived as a progress stopper for Gregory, the guy they really want to take the job.
In Crawford's case it's easy. He's a JAG DE and he can still play DT.
But Gregory can't be expected to start over Griffen or any big money FA, especially with Aldon Smith, Armstrong, Jackson, and maybe Anae competing for snaps.
Goodell knows Dallas wants Gregory bad so he's taking his time reviewing his case, if he's even reviewing it at all.