http://goallineblitz.com/game/replay.pl?game_id=1950089&pbp_id=1223360 Assuming you mean this team (since it's where your only player plays) that was a 13 yard punt, and he returned it.
http://goallineblitz.com/game/replay.pl?game_id=1950089&pbp_id=1225056 12 yard FG returned.
http://goallineblitz.com/game/replay.pl?game_id=1950089&pbp_id=1225859 14 yard punt.
So no, there is nothing about punt distance that determines if it's allowed to be returned.
http://goallineblitz.com/game/replay.pl?game_id=1950092&pbp_id=728318 16 yard from game before previous 3 replays.
1st game of pre-season
http://goallineblitz.com/game/replay.pl?game_id=1950095&pbp_id=216774 fair caught. RG on punt team is within 5 or so yard of the returner.
It's about the distance of the closest punt team player to the return man. The higher the punt (especially short punts) the more likely a player will be able to reach the returner and force a fair catch