I'm sorry, but giving someone rookie of the week for an in-the-grasp call is pretty weak.
What's "pretty weak" is that you watched the game and you don't even know what went on.
Merling not only got a sack, but he was directly involved in two turnovers..
Merling caused all the pressure on Cassel that led to Cassel throwing it early causing the interception (and causing that bad pass in the first place).. That play was obviously bigger than the sack he had earlier because it got the defense off the field (and held NE to zero points) immediately giving the dolphins the momentum switch in the game after NE was driving deep in Dolphins territory.
Then, on another play later in the game, Merling recovered a fumble. Not only did he recover that fumble, but his great initial upfield pressure/burst forced the ball carrier towards Porter for the strip.. And then Merling had the presence of mind to beat a Patriot to the ball (as a Patriot was closer to the ball initially).
So Merling was a big part in 2 turnovers.. And turnovers have been a problem for the Miami defense for a year and a half now....
Furthermore, Merling was very stout against the run driving blockers backwards creating space for LB's and safeties to make numerous positive plays.
Watch the game closer next time.