In terms of submission/Brazilian Jiu Jitsu skills, we know that he owns a brown belt in Brazilian Jiu Jitsu under the Nogueiras, and that means something, even if we haven't seen him on the ground much.
What Cain Velasquez brings to the table: Cain Velasquez has one of the greatest motors we have ever seen in the heavyweight division. The guy can fight full tilt for an entire bout due to what amounts to some amazing cardio. He's also one of the better wrestlers in the heavyweight division, and possesses solid striking skills to boot.
In terms of power, he hits hard, but not ridiculous hard. Still, the former heavyweight champion is definitely a well-rounded guy, even if his submission capabilities are apparently somewhat limited (no wins by submission).
Junior dos Santos vs. Cain Velasquez Prediction: The last time these two threw down, Dos Santos tagged an all too eager to strike Velasquez early and ended his night. This time, expect Velasquez to try and make this one into a ground war. Beyond that, expect him to be a much more careful striker.
Do I think that Velasquez can bring Dos Santos to the canvas? Yes. Do I expect him to finish him there? No, though cumulative effect over the course of several rounds could end things via a cut, etc. That said, the current champion is the better striker. So the bottom line is, can Velasquez and his awesome cardio take the champion down over the course of five rounds? Further, can he avoid being knocked out while on his feet?
In the end, I think Velasquez can this time. He should fight a smarter fight.
Cain Velasquez defeats Junior dos Santos by decision.