Incentives or performance bonuses in the NFL fall into two categories:
Likely to be earned or Unlikely to be earned.
If incentives are likely to be earned, they count against that years cap hit. If they are unlikely to be earned, they count 0 towards that years cap but if earned, are charged against the next years cap number.
I imagine most of his incentives are unlikely to be earned, meaning that roughly $2 mil remaining from the reported numbers, would either never materialize or be paid out next year.
Bottom line for me: We get a very experienced player on the cheap. And if we have to shell out $$$ next year since he met those performance bonuses, it will hopefully be well worth it!