What I saw from Williams from recent seasons is an aging star player who still can be productive. However, I don't think he's expecting to be given a featured role with his new team despite his remarkable resurgence last season starting in place of an injured Ronnie Brown. I've to believe that his career is winding down and I don't view him as a player that desires to play pass two more seasons at the most. Hence, New England could be an ideal situation to wrap up your NFL career.
Williams is a veteran that could excel playing behind a younger running back. He's a career 4.1 yards per carry, so he moves the ball. Also, his carries have been considerably low (by comparison to earlier in his career prior to 2004) through the pass three seasons. Again, Miami needed to lean on him last season to handle the bulk of the workload in Brown's absence. He shouldn't expect that scenario playing out with the Patriots and a healthy Green-Ellis.
If Belichick were to sign him, I wouldn't expect him to have the same impact as, let's say, Corey Dillon since he presumably won't be signed to be the starter. On the other hand, I expect him to be more durable and productive than Fred Taylor. Also, Williams' addition would allow Danny Woodhead to be more of a third down running back. Actually, Williams is still a capable receiver out of the backfield. Imagine Brady on third down and long having Williams and Woodhead as options besides the wide receivers and tight ends.
If Williams decides to sign with New England, he'll get an opportunity at a larger role because Belichick would figure out ways to get the most out of his abilities. He can still be a dual threat for a team under the right head coach.
