According to Deadline, A.J. Cook did not have her option picked up and Paget Brewster will have reduced episodes. I believe the story should be referring to Season 6, as well. For me, cast continuity is important and I already didn't like Lola Glaudini and Mandy Patinkin leaving, although it was Glaudini's choice to leave.
Criminal Minds is a show that doesn't have large ongoing arcs or even a deep backstory on each character. It works as an ensemble, each character contributing to catch a criminal. The formula works, so I don't want to see it messed with.
But I can see why CBS would make a drastic move like this. If money is really the problem, every character is expendable, even Hotch. I guess we'll see how the show fares once it comes back in the fall.