it seems campbell isn't officially bound to fight guzman yet. pac vs. campbell can still be made for november.

"When asked why Campbell has not been frequently discussed in the Manny Pacquiao Sweepstakes, Trekas replied, "We let Top Rank know that Nate wasn't officially bound to do the Guzman fight, and that we would skip him and fight Pacquiao in November if they were interested. They were already committed to the Valero deal."

Campbell vs. Guzman in Jacksonville? Bradley in Co-Slot? - Boxing News

I've also read Arum just offered Nate $3 million to fight pac.