Marino, who is now 39, retired from the game in 2015 after a career which saw him represent clubs in Argentina and Chile.
But it’s his spell at Universidad de Chile – in which he raised three titles under the tutelage of former Argentine national team coach Jorge Sampaoli – which has come under scrutiny not for what he did on the pitch but for what happened off of it.
According to ex-teammate Gustavo Lorenzetti, Marino once explained his absence from training by claiming that he had been abducted against his will by a team of extra-terrestrials.
“Guillermo says that he arrived late to one training because he was abducted by aliens,” Lorenzetti explained to the publication Lado B.
“He gave us the entire explanation of what he felt and the rest of it.
“There are cases where the player says: ‘I left and I came back two days later because I was kidnapped by aliens’. But Guille is not that kind of player. Guille was a very proper guy. Everyone knows him.”
What was initially received as a joke, Lorenzetti says, soon turned to astonishment in the dressing room as Marino shared his alleged experience to his teammates in intricate detail.
“He started to explain that he was suddenly lost and abducted by aliens,” Lorenzetti said.
“He explained that they take out your soul, analyse it and all the while on the journey they are looking after you. He said something like that.
“Honestly I believe in aliens. He gave a great explanation and we’ll have to believe him. So other types of channels will have to call him so he can tell it better. But in any case: he was abducted by aliens.
“I don’t know if Guille would have told [Sampaoli] the same story, honestly. They must have had a chat afterwards. But knowing Guille, I think he must have believed him. What can you say? This is worthy of the Discovery Channel or something.”
Marino’s excuse for his tardiness is perhaps the most original, but follows a litany of strange and bizarre explanations from footballers to explain their absence.
Goalkeeper Santiago Canizares missed the 2002 World Cup after saying that he dropped a bottle of aftershave on his foot, while France’s Philippe Mexes was reported to have been injured while tanning in a sun bed.
Real Madrid star Marcos Asensio also missed time after sustaining an infection while shaving his legs prior to a game.
None of these excuses can quite rival that of Guillermo Marino’s run-in with little green men, however.