Simply put the Eagles messed up. Nnamdi according to Pro Football Talk had to play 90% of the defense snaps in 2012 to guarantee $4 million of his $15 million 2013 salary. It was an automatic $4 million, so regardless if he is on the roster or not he would get that money.
The Eagles were out of playoff contention for a long time and it wasn’t like Nnamdi was playing well. They could have easily benched him and saved themselves $4 million or given themselves more leverage in trying to get him to renegotiated this contract.
What probably happened, was Andy Reid didn’t care, since he was getting fired anyway, so he wasn’t monitoring these type of things. Now, Nnamdi knowing that he has $4 million in his pocket regardless, can make a better a decision on if he wants to renegotiate his deal or not.