Sheffield United's decision to grant Ryan Leonard permission to play against them tomorrow has sparked plenty of debate.
Whether or not it is set to become commonplace could become apparent when Wigan Athletic visit Bramall Lane next month.
Leonard, the United midfielder, joined Millwall on a 'loan to buy' basis during the summer transfer window, with his move set to become permanent on January 1.
Three weeks earlier, Bramall Lane's hierarchy entered into a similar arrangement with Paul Cook's side when Evans headed to the DW Stadium.
With United scheduled to meet their rivals from Greater Manchester in 30 days time, if Evans is also eligible for selection it would suggest they have adopted a laissez-faire approach to players destined to depart.
Although Leonard's situation is unusual, it is not without precendent.
In 2014, Chelsea's Thibaut Courtois, then on loan at Atletico Madrid, beat his parent club in the semi-finals of the Champions League.
Twenty-seven years earlier, Peter Withe scored twice against United after returning temporarily to Birmingham City. Goalkeeper Roger Hansbury featured for the hosts after travelling in the opposite direction.
United must hope history does not repeat itself at The Den.