Biggest performance drop-offs

Robert Griffin III has struggled this season for Washington. AP Photo/Tim Sharp

We enter every NFL season with preconceived notions about player performance. History has taught us what to expect from players, and the most logical thing to do is expect it to repeat itself. Only it usually doesn't, because if it did, the league would be a very boring place.

Whether it's Father Time catching up, an injury slowing someone down, or just poor play brought about by a change in personal or professional circumstances, sometimes players just don't live up to what we expected from them.

With that in mind, here are the five players whose grades have fallen off the most from last season to this one.

Robert Griffin III, QB, Washington Redskins: -37.5
It was always going to be hard for RG III to replicate his fantastic rookie campaign. He finished 2012 with a plus-30.6 grade that pushed him to ninth overall in our quarterback rankings. This year? He's got the fifth-lowest grade, with his adjusted accuracy percentage dropping from 79.6 percent to 72.8 percent -- and he's only completed four deep balls all year. He also hasn't been the running threat he was last season. All of these factors are playing a big part in the mounting pile of defeats for Washington.