Not So Fast
Both local reports (EVT and AZR) hedge their bets on Leinart's possibly starting. Even an ESPN reporter - after Clayton reported it would definitely happen - recapped the report by saying that it "possibly could happen."
So the first thing is not to jump to conclusions until the Cards have something to say.
Secondly, the Cards have announced a 10 pm (AZT) press conference at the Stadium (they didn't indicate what the topic would be. It could be something completely apart from a QB announcement).
The media may be picking up the report correctly, but I think it would make sense for DG to leak it regardless of whether or not he planned to replace Warner with Leinart. It gives him the option of (a) making the move, (b) not making the move while at the same time firing a warning shot across Warner's bow or (c) setting the stage for a move to Leinart later on this season if events dictate.
It could be a PR move (dictated at least in part by ownership) to minimize the bad fan karma in the wake of the Ram loss by diverting attention toward the debut of our QBOF (I hope this isn't the case - football decisions and not PR decisions should dictate roster moves).
Or it could be an internal move designed to accomplish the same thing - i.e. get the players out of their collective funk over the Ram loss and refocus it toward "the new Leinart era." (Note - This is not a good idea when you have a young team that needs stability, structure and predictability in order to develop. But it may be a good idea if you have the feeling some of your players are a bit complacent about their starting roles (i.e. Macklin and now maybe Warner). So the move - if it takes place - could be more a function of locker room chemistry than PR. I wouldn't rush to judgment just yet.
Finally, with the exception of the turnovers, our passing offense has looked good and our running game has started to get in synch. In theory, an offense consists of a number of interrelated components, so you'd think it would be easier to straighten out one aspect of Warner's game than it would be to make so dramatic a change - one that would probably require considerable additional tinkering with the offense. And it should be pointed out that, despite playing like a veteran in preseason, Leinart has never played a regular season game and had to deal with its faster tempo & complex, confusing "non-vanilla" defenses.
That said, it's DG's call (That's why they pay him the big bucks). Barring anything really bizarre, he's our HC for at least the remainder of the season. Whatever he decides, we ought give him our support.