As the most scrutinized position in sports, the NFL quarterback has his every move analyzed under the microscope.
In many instances, this highlights inconsistencies among several top passers who are a few unheralded mistakes away from reaching superstar status.
After a year removed from the game, Peyton Manning has returned as the same steady force. His 204 passing yards last week, which resulted from the Denver Broncos running early and often, represented a season low.
Reigning MVP Aaron Rodgers has not thrown more than one interception in a game since the 2010 NFC Championship.
These guys are as reliable as they come. But below the premium class rests a group of quarterbacks who play brilliantly at times but poorly on many other occasions.
Eli Manning leads this class of up-and-down signal-callers. He outplayed Rodgers and Brady en route to his second Super Bowl ring last winter, but he's still prone to eye-gouging mistakes that leave New Yorkers wondering if they're watching Mark Sanchez.
These five quarterbacks frustrate NFL fans with unrealized upside stunted by stints of mediocrity.