I'll betcha that the G-men are seeing this as a protective move for Eli. I can see Warner being the starter for about half the season and then Coughlin pulling the switch (with Warner's play not being the biggest factor). It gives Eli a safety blanket if things look like they are getting too hot for him on the field.
Also, it helps the NYG front office cover themselves from the NY media and fans that would pretty much crucify them if Eli comes out of the gate and falls on his face.
I think Eli has excellent potential and if they can keep him alive and well and build around him, he will do well. I just think that the drama around the whole draft day trade and the comments by all parties have dug him a perception hole that he needs the NYG front office to help him dig out of. Picking up Warner and letting him "compete for the starting job" may help them out with this.
Who's the Man?... J-Man, that's WHO!
Eat 'em Up, KATS!