Context: The Jets were thoroughly dominated by the Patriots; they scored five touchdowns in the second quarter, three of them in a span of 52 seconds of game clock. The first came on an 83-yard pass to Shane Vereen after the Patriots recovered a Shonn Greene fumble. On the Jets' ensuing drive, Mark Sanchez fumbled after running into lineman Brandon Moore and Steve Gregory ran back a 32-yard score. The play later became known as the "butt fumble". The third touchdown came on the ensuing kickoff, Devin McCourty forced Joe McKnight to fumble, which Julian Edelman recovered and returned for a third touchdown (he later caught a 56-yard touchdown pass from Tom Brady). With the huge loss, the Jets fell to 4-7, and were swept by Bill Belichick's Patriots for the sixth time.

Question: Which quarterback was responsible for the butt fumble?

Answer:
Mark Sanchez