Joe is very lucky to have this match, b/c Diego should be fighting for the belt at this point.
I posted earlier in defense of Riggs, but in defense of Sanchez, he can win by sub, GnP, or decision as he is a much more complete fighter. He has excellent cardio plus he's got the whole consistency thing on his side. Diego is much better on the ground and I don't see Riggs being able to keep top control on the ground. Nor do I see Riggs keeping this fight standing with a mediocre takedown defense and Diego's superior wrestling skills.
And then there's the whole weight and conditioning issue. Riggs is poor at cutting weight so assuming he makes weight, he's too big for WW, he loses too much water weight to get down to 170 so its going to take a lot out of him. How long can he last w/ The Dirty?