Yes, they fought before, and Bader got the better of Rampage. This fight also makes little sense for Bader, who has put together a solid run at light heavyweight recently. That said, the Rampage that showed up against Bader in Japan was probably the worst Rampage of Quinton Jackson's career. He'd probably like to avenge this loss, and the pairing has enough name value that it could headline a Fight Night or co-headline a Pay-Per-View. However, it would likely end in Bader controlling Jackson with his wrestling again, and if Bader were to lose, he'd be even further from a title shot.