Who will be Eli's backup?

Due to the fact that the New York Giants have Super Bowl champ Eli Manning starting at QB, their QB issues are not debated with as much vigor as their MetLife Stadium co-tenants, the New York Jets. The Jets are in a tough spot, with starter Mark Sanchez underwhelming in 2012, the world's most famous backup Tim Tebow potentially on the way out, and third-stringer Greg McElroy not projected to be an impactful starter at the NFL level. But the Giants do have one QB issue this offseason: their own backup -- the much less heralded David Carr -- is an impending free agent. So to whom will they turn as Eli's understudy?