You can watch here: http://esporte.uol.com.br/lutas/val...farto-e-morre-aos-33-anos-em-campo-grande.htm
He was on the ground for what... 15 seconds?! Are you trolling? ... Wait, this is Sherdog. Why am I even asking?
JDS only needs to be good enough to defend subs and, most of all, minimize damage from Cain's G'n'P. If Cain does manage to get him to the ground, I see it happening in the later rounds. Then it'll be more to do with how JDS copes with exhaustion rather than how good his BJJ is.
Meh That 15 second clip of them rolling on the ground didn't really show much, most of what I saw was JDS overpowering the guy. You get a better look at his ground-skills when he and Machida are rolling in practice. Also that isnt Cain on top of you, Cain is an entirely different beast on the ground then this guy. Hopefully Cain shows us his real ground game against an elite wrestler, this is fluff.