Pellegrino believes there's nothing Diaz can show him that he hasn't already seen. To wit:
Kurt Pellegrino: Cardio. Cardio, cardio, cardio. When I got to the UFC, I fought Drew Fickett (at UFC 61), and I wasn't doing my cardio like normal. I just got married, I took that fight on a month's notice. Actually, three weeks, so I just worried about sparring and, you know, all the wrong things to do in MMA: sparring and grappling. Everyone does that, you know. (But if) you train with somebody and do a lot of cardio, cross-training, it's a lot different at that level.
So for this fight, I know he's good on the floor. I'm ranked in the world in grappling. I've beat world champions. I went to Abu Dhabi. So I don't mind. If this kid comes in here, and I take him down and he submits me, then he deserves that victory, he deserves his hand raised, I'll be the first one to raise his hand. But stuff like that I just don't see happening, you know. He's a very tough opponent, but I think I'm going to be a little too much for him.
I've always had my doubts about Pellegrino, but he seems to have everything Diaz does as well as better wrestling. That might be enough to take the fight.