Obviously the football agents want the Remain side to win as it would guarantee their percentages of transfer fees. If the Leave camp wins it could reduce the number of EU players coming to the Premier League. This would result in more home grown players getting Premier League experience leading to a better National team........possibly.
This could help the National team if EU players failed for whatever reason to obtain a work permit for the UK should the Leave vote wins, resulting in more English players in the Premier League.