Yes there is truth there. It's more between him and former AD Tom Jurich. Since Jurich has been canned, it's one more reason why he'd jump at the chance to come back.
Steve Kragthorpe was stunningly bad during his time here. There's one story from that time that's been told and retold. Right before a game DC Ron English is talking to the team getting them hyped when Kragthorpe walks and proceeds to spew some kind of weak bullshit, killing the mood. As soon as he walks back out of the room, English tells the team "ignore everything he just said".
Jeff was mad Jurich didn't give him a chance when he finally canned Kragthorpe. It worked out in the end with Charlie Strong, but it still stung Jeff.
Now there's rumors floating around about Petrino. Something he's been doing is going to give AD Tyra the ability to fire him with cause. Shocking, I know.