The problem with Z is that there's a good chance most of his stellar games will happen while he's sitting on your bench after he burns you a few times, then once you reach reasonable comfort level you'll put him back in your lineup and he'll burn you again, it's a nasty cycle with that guy, I won't go near him.
I love Fat Z and have been targeting him as a sleeper this year. He improved on his K/BB and K/9 rates last year and the way he's been this offseason and Spring there's no reason to think that he'd regress back.
What I find most amazing is that Fat Z is only 28 years old (turns 29 this summer). I think this is the year he shows he's the ace of the rotation that we hoped he would become.
Pitchers like Zambrano rarely age well. I think it is much more likely he misses half the season and posts a 4+ ERA than he shows he is the ace they thought he would be. His arm has been abused his entire career so far and when young guys get abused they either break or they go the path of Livan Hernandez and burn out young.
He is still worth a shot late though, he probably has one season left in him where everything goes right and he has a good year, maybe it will be this year.
re the concerns about Z's arm, I don't think Zambrano throws all that hard to be all that concerned about him blowing up? I am more concerned about his propensity to flip out in the middle of games and have temper tantrum fueled meltdowns that cost him (and the Cubs...) games. Then it takes him another outing or two to get his head back out of where he stuck it. I'm a homer too, and like Zambrano ok as a fan but am not targeting him for fantasy b/c of the head issues.
Zambrano was overrated for years IMO, even the years he was considered a fantasy ace. Now I think it has swung the other way around and this year I am finally owning him in some leagues. Just last night I took him with pick #173 and couldn't be happier.
In a "down year" Z had a 3.77 ERA and a 1.38 whip along with 8.1 K/9. Not great and definitely not an ace, but not too bad either. If you take out his first outings after his two DL trips (and I would never start a mid-tier pitcher like Z right after he came off the DL) he had a 3.37 ERA, a 1.35 WHIP and 7.9 K/9. That's not "he sucks" territory.
His WHIP isn't great, but he is a career 1.30 WHIP guy and he's been hovering above and below that the past few years. Again that's not great but it isn't a single-handedly killing your WHIP guy. He's a guy that's been under a 4 ERA each year for the past 8 years, which not many guys can say that - not Carpenter, Sabathia, Hernandez, Haren, or Halladay to name a few.
It's easy to bag on Z because he has very little upside, has such big-name recognition and has been over-hyped for so long. But he isn't a bad pitcher for fantasy when you can get him around the time others are taking Slowey and Wolf types.
I would definitely rather have Lilly than Z. I think the same was true last year, and the same will be true this year, even with a few starts missed by Lilly to start the season. (it's not as if Big Z won't miss a few starts either).