The rookie receiver gets his first Lambeau leap on the ground rather than through the air. The Green Bay Packers’ running game struggled in Tampa last week without the threat of speed to stress the Tampa Bay Buccaneers’ defense horizontally. With wide receiver Christian Watson back from injury against the New England Patriots on Sunday, that threat is back, and Watson delivered for the first time on the immense promise and potential he carries. Early in the second quarter, Watson took a jet sweep around the right side of the line, using his ludicrous speed to get to the edge.…