Ansah, a rookie defensive end out of Brigham Young, scored just 3:49 into the contest and the Lions stayed in front the rest of the way in their exhibition opener.
Sanchez went 10-of-13 for 125 yards and a touchdown, a 26-yarder to Jeff Cumberland late in the first period that brought the Jets within three.
Detroit starter Matthew Stafford, who has started every game for the Lions over the past two seasons, threw just eight passes and completed three. Shaun Hill came in to complete 11-of-18 for 136 yards and found Matt Wills with a 15-yard touchdown pass late in the first half.
New York threw the ball 39 times and ran it on just 16 plays.