I have him and Patterson down as targets to sneak away in my league. Webb's problem is keeping his control together--Patterson's issue is that terrible offense he'll be pitching for. But these are guys who can help you alot, and even better, won't hurt your carefully crafted ERA in a ROTO league.
Webb has that great combination of GB% and K/9, and other posters pointed to O-dog and other improved defense helping him a lot.
He'll more than likely be facing other team's #1's though...although in the NL West ..outside of Peavy, thats not much (Penny, Schmidt, COL)