On punts there will be two guys on the punting team lined up wide, like wide receivers. ... The gunner's job is to try to get down the field as fast as the kicked ball and tackle whoever catches it. In the best case, they get there just before the ball and make the other team afraid to try to catch it.

Source: http://football.calsci.com/Positions13.html

I believe they need speed, vision and tackling as primary stats.
They could probably also use: agility, strength.