I saw him move his leg, but you’re right the dolphin was WAYYY out of bounds. The player had to be be close in order for the trip to work. The guy only moved his knee about 6 inches.
It looks the the Jets were running the return to that sideline and had two players sealing the Dolphin outside man out of bounds.
The coach needed to get out of the way rather than leave his leg out there.
That's a pretty common soccer foul by a player who gets beat on the dribble. Once he's on the wrong foot he leaves his leg out there for the offensive player to run into. It's more a foul by omission than by commission.