With Perpignan currently topping the standings in France's premier division, the Catalonia-based outfit are guaranteed a place in the top four.
Unfortunately for Hines, that semi-final would take place on either May 29 or 30, with the latter being the day of the Lions' first tour match in South Africa.
The final would then take place a week later on June 6, meaning that if Hines stayed with Perpignan and they reached the last two, the former Edinburgh player would not be available for the Lions until the clash with the Sharks on June 10, four matches into the 10-game tour.
"I have a torn heart but what can I do?" Hines told L'Equipe.
"If I am not in London on May 18, I will not be selected.
"Last year I was a substitute for Perpignan in the play-off semi-final. Imagine if I were to refuse the Lions and the same thing happened to me?
"Representing the Lions is the creme de la creme, the squad of squads, the best players from four countries. It is difficult to explain, it is something all British players want to experience."
Although his decision will be welcomed by Lions supporters, fans of his club side have already voiced their disappointment as Perpignan go in search of their first French title in 54 years.
For Hines, however, the chance to take part in his first-ever Lions tour was too good to pass up.
"They (the supporters) said to me, 'Why are you going? You have a choice'.
"They don't understand the importance of the Lions for a guy like me, but they want Perpignan to have the best chance of winning the title."