Arizona has clinched the NL West, but I haven't seen confirmation of this fact from any of the major media outlets. ESPN, Yahoo and MLB.com all list their playoff status under the "clinched playoff spot" designation.
As far as I know, only three people in the world might be aware of the current state of the NL West: Myself, Clay Davenport, and the lines manager at The Greek, the only sportsbook so far to actually pay Diamondbacks futures bets.
The Padres suffer a big blow, as they have to use Jake Peavy on short rest tomorrow, leaving his status for the NLDS in doubt. They may be able to start him in games 2 and 5, or pull him from tomorrow's start early if their playoff spot appears certain.
If I managed the Friars, I might even give tomorrow's start to a capable reliever--Heath Bell?--keeping Peavy locked away behind some "Break in case of fire" glass. If the future is still uncertain after a couple of innings, bring Jake in for seven innings of no-hit relief, Pedro-in-the-ALDS-style.
This will never happen, of course, but it never hurts to think outside the box.