Let's pump the brakes for a minute; Reebok was a player in the running industry back in the 80s mainly because their product was less abysmal than anyone but Nike, plus the competition was far less. Nike was the player, and still is, Brooks, Tiger and adidas had very few athletes and their products were horrible. Consider Converse and Etonic were even players at this time.
Reebok had money and spent largely on Steve Jones, Ed Eyestone, Arturo Barrios and a few other top mexican runners. The product remained less than desirable and most if not all of the above very much trained in something else and their racers were in some cases a competitor brand with stitched over logos*, if not a customized shoe. *See the James Worthy principle.
So Reebok has a few descent models out now. There emphasis remains on the fitness, cross trainer crowd. Why would Reebok dump millions into their on again, off again interest in performance running? Why would Fox, knowing this history first hand, leave for this brand?
Unless anyone actually has a copy of Fox is signing with Reebok, I' have second thoughts. Why not Nike starting a Nike-Boston or Nike East program aka late 1980s early 1990s. CUSE is a Nike school and Fox was a long time Nike runner with the exception of a few years with Brooks. Knight has worn Nike his career as well.
adidas has a much stronger presence in performance running than Reebok and that's still marginal at best in the USA. I'll not be shocked if it's Reebok, but I wont' be surprised if its not.