Rule 12, Article 2
Article 6: Unnecessary Roughness: There shall be no unnecessary roughness. This shall include, but will not be limited to:
(b) contacting a runner when he is out of bounds;
Note: Defensive players must make an effort to avoid contact. Players on defense are responsible for knowing when a runner has crossed the boundary line, except in doubtful cases where he might step on a boundary line and continue parallel with it.
This seems in line with other UNR calls where the runner is technically still airborne, but clearly crossed OOB to end the play.
If I remember the play correctly, the Jets' player contacted the returner after he had crossed the boundary and was clearly going to be OOB.