I thought it was interesting that Chelsea recently decided to recall on-loan defender Nathan Aké from Bournemouth. The Dutch international joined the south coast club in August and has put in a string of excellent performances for Eddie Howe’s team, including scoring three goals. The most notable of these was his last minute winner against Liverpool in Bournemouth’s dramatic 4-3 win.
This goal could prove to be important to Chelsea, as it denied rivals Liverpool a point. Another influential player in the team that day was Arsenal’s on-loan midfielder Jack Wiltshere who played a full ninety minutes. Wilshere has played 70 minutes or more in 12 of Bournemouth’s last 15 games. The only two games he did not appear were home and away to his parent club Arsenal.
Is this inter-league loan system fair? Effectively, clubs can loan out agents to compete against rival teams, who are then prevented from playing against their parent club. While Liverpool suffered at the hands of Aké, they too have an inter-league loan, with Jon Flanagan currently a member of the Burnley squad.

Due to possible conflict of interest, it is hard to see how a player could play against their parent club. Thibaut Courtois's appearance in a Champions League semi-final being an obvious exception. Most players today don't celebrate goals scored against ex-clubs.
Whether or not it is fair is open to debate. I think the spirit of the game would be better served by loaning players to other divisions within the Football League or other countries.