There was talk from the time he signed that contract that it would have to be re-negotiated if the packers kept him past 2014. McGinn had this to say recently about Peppers:
I think the Packers would like to lower his cap number in 2015 because of the big name FA's they need to sign (Cobb/Bulaga/Williams). The guys they will need to sign in 2016 don't carry as high a price tag.The assumption is that the two sides will restructure the final two years of his contract and he'll return in 2015.