He certainly still has gas left in the tank to play 2-3 more years, but I believe the days of being a continual threat as a pass rusher from OLB are now behind CM3. He should now be in a rotation with Perry and some other younger guys, and he should expect time at ILB as well.

If he wants to stay in Green Bay for another 3 years, I would offer to extend his deal 2 more years for a total of around $21M. Give him a $6M signing bonus and roughly $7M / $5M / $3M base salaries for the next 3 years. That reduces his cap number this year by about $2.5M and ensures his cap number will reduce along with his expected contribution in coming years. If he's not willing to accept an offer like that, then you let him play out his deal this year and wave bye-bye after 2018.