I think it made sense for these reasons:
1) Dillon only had a 2-year deal IIRC when he got to NE. After his outstanding year in '04, the Pats had to show their feature RB that he had job security.
I'm not sure. Players sometimes play better when they DON'T have that security.
2) It gave the Pats an out after 2 years if Dillon wore down (which they figured he would). Also gave them 2 years to find his replacement, which they did.
But it was an expensive out!!!
3) Dillon had some incentive to play at a high level in '05 and '06 with the 3-year option looming. Injuries and father time limited his contributions, so unfortunately for Corey he could not secure the last 3 years of the deal.
But he'll still earn $5m from us over the next 2 seasons?