"He might want to watch the final," Vatican spokesman Federico Lombardi said of Francis, formerly the archbishop of Buenos Aires Jorge Bergoglio -- a fan and card-carrying member of the San Lorenzo de Almagro club since childhood.
But a Vatican source said he "excluded categorically" the prospect of pope emeritus Benedict XVI, an academic theologian with a penchant for classical piano, sitting down in front of his television set to watch the face-off.
"It's really not his thing, he is not a fan. It would be like inflicting an infinite penitence on him at the age of 87," the source said, adding: "He has never been able to watch a football match from beginning to end in his life".
Benedict did like to keep informed on football results while he was pope and could at least comment on the big matches but he did not follow his home team, Bayern Munich.
That has not prevented a few jokes from doing the rounds in the Vatican ahead of the big game at Rio de Janeiro's Maracana.
Father Thomas Rosica, a member of the Vatican communications, quipped in a tweet: "Unconfirmed reports in Italian media: large quantities of mate and Fanta delivered to Vatican for private event Sunday" -- a reference to the famous Argentine tipple and the German fizzy drink.
- 'There would be a war!' -
The contrast could not be greater between Benedict and Francis, who is regularly updated on the activities of San Lorenzo and a team delegation came to the Vatican in December to give him their trophy after they won the national championship.
They also gave him the club's red-and-blue team colours with the words "Francisco Campeon" (Francis Champion) written on the back and the goalkeeper's gloves -- used in a save that helped them win the tournament.
When he does his weekly tours of St Peter's Square on his "popemobile" before general audiences, the 77-year-old pontiff is regularly pelted with football jerseys and he has extolled the virtues of sport as a spiritual activity.
While the Vatican said Italian media reports about a "two popes final" are off the mark, its own official daily -- the Osservatore Romano -- earlier this month predicted that Argentine and Germany would reach the final.
In an unusual article for the normally conservative paper, former player Tommaso Damiani, a staunch Catholic, said that "there could be a final that will go down in history because of its unusual supporters" -- Francis and Benedict.
Ahead of the final, Italy's RaiNews made a photomontage with a real image of the two popes kneeling side by side -- except that each is depicted praying for their own team.
Conscious of his role as head of the Catholic Church around the world, Francis himself has been careful not to make any predictions about the World Cup or to reveal his passion.
There was one slip earlier in the tournament, however.
The Vatican affairs news agency I.Media reported that when a group of the Vatican's Swiss Guards invited him to watch the Argentina-Switzerland game in their barracks, he declined the offer saying: "There would be a war!"