When the Patriots opened up the game against the Dolphins in a 3-man defensive front, most wondered why defensive lineman Tommy Kelly, the player on the roster best suited to align in a 3-main front, was released earlier in the off-season. 

Turns out, Kelly asked for the release.  He didn't want to be on the Patriots. 

Accoridng to Josh Weinfuss of ESPN, Kelly sensed things were "changing" and didn't like where the direction was going. 

"I saw what was going on," Kelly said. " I mean, you’re starting me, but you’re taking me out.  I don’t know why you're taking me out.  I had a situation with my deal and I saw what he was doing, so I got on my agent and we got together and I was just happy." 

Kelly's contract was incentive-laden and his value was directly related to his playing time. 

According to PatsCap.com, Kelly had the following step-ups based upon playing time:

20 percent -- $95,000 30 percent -- $195,000 40 percent -- $345,000 50 percent -- $495,000 60 percent -- $645,000

So if the Patriots viewed Kelly as a rotational figure instead of a mainstay, Kelly would find himself short of nearly half a million dollars. 

According to Pro Football Focus, Joe Vellano- who took Kelly's starting spot- played 50% of the snaps on defense.  It wouldn't be hard to see a better player earning 60% or more. 

While Kelly's concern that he wouldn't earn all of his playing time incentives doesn't seem to be playing out in reality, it's a very fair concern for him and reasonable for him to ask to be put in a different situation.