I know this is going to sound incredulous, but I have the feeling Lopez is going to knockout Canelo. What I mean is serious KO, like chicken dance sort of stuff, like Juanma throwing the water bottle at the ref kind of stuff. Here are my reasons.
1.) Originally I had the fight as a sure thing for Canelo: he's bigger, stronger, rather skilled for his size, can take a punch, a decent counter puncher, and underrated speed. He throws in combination, can have decent defense at times, and can move his feet. He's patient, wise beyond his years, and is methodical in his approach: i've never seen him lose his cool. He's a good overall fighter with a strong punch.
2.) Lopez was never a heavy hitter at 140 then yet 147. At 140 he looked gangly, skinny, and really just a thin, wiry kid with a tough heart and relentless pressure. However, at 147 he did look a bit of a monster with extra muscle and thickness all around including his legs, calves, and shoulders. He can also take a punch too as he was never officially down from Ortiz who is basically a jr. middle or middleweight. Ortiz is faster than Canelo, and probably has a more dynamic punch whereas Canelo has more weight and "thud" (think Cotto's punch vs. a Mosley punch) behind it.
3.) My gut feeling is that Lopez has been putting in the work, has been able to take and give punishment to his sparring partners, and that leading up to the fight he will peak and will overcome the strength/size deficient. If he does that than we have an even fight. He is still taller which means if he fills out he'll actually be the bigger man. He has reach advantage which might mean a lot.
4.) Lopez is like the terminator: he'll never stop until you're dead. He'll keep coming at you relentlessly and in a way that's more intelligent and systenatic than Margarito or Rios. It could be b/c he's skinny, taller, and simply more athletic than those two or b/c he's more of a boxer than those two.
5.) Canelo showed in the Mosley fight that he gasses out after round 5. He started slapping his shots, and much of the snap on his punches were gone by rounds 8 & 10. He also lost a lot of killer instinct once it was apparent that Mosley was able to take his best shots and that he didn't have a shot at knocking him out. I feel guys with too much upper body muscle including Canelo, Berto, and Pascal tend to gas out in the later rounds b/c the muscles get tired. Big muscles get in the way of flow and mechanics and tire you out fast... Cotto, who's not overly muscular is naturally top heavy and we can see he loses steam after round 7 & 8 every time. We've also never seen Canelo take a steady diet of punishment throughout a 12 round fight. This will be a good fight & test. Rhodes, Baldomir, Cintron, Gomez, or old Mosley are not the level or prime that is Lopez is in now.
6.) I think it'll be a real dog fight and if can even knock Canelo off his game plan once or ding him good, he'll just wear him out and go in for the kill. This is me going out on a limb. I'm ready to serve or eat crow, so here I go!