its too early on in Bretts career for him to pose a threat. The guy is still green in the ring, and only recently started focusing 100% on fighting, and not having to worry about an actual job as well taking up his time.
if rogers was a more developed fighter, he may be a better test for Fedor, but i just dont see him being much at this stage in his career. Fedor has disposed of guys just as strong, and 10x more experienced that Rogers.
IMO, the only one to REALLY give Fedor a touch fight, was CropCop. and Rogers is no where near the level that CroCop was on.