The report suggests PSG will offer Chelsea around £41.5 million for the Brazilian's services.
"I build my team around Oscar playing as my number 10," Mourinho said in January, explaining his decision in sanctioning Mata's £37.1 million departure, as per BBC Sport.
And for footballing reasons, the Chelsea boss is right to maintain that stance. The bigger picture says otherwise, though.
In the world of business, Oscar's value as an asset to Chelsea is far greater than that of his value as a player.
PSG are perhaps undervaluing him at the £41.5 million figure quoted, when factors such as his age, talent and potential are taken into account. They'll need to make a higher offer to convince the Blues to sell, but if PSG were to offer something substantial it would be folly not to pursue a deal.
It's a cliche for a reason: Whether it's Cristiano Ronaldo or Juan Mata, football has shown us throughout the years that every player has their price. And so, too, does Oscar.
Chelsea accepted United's offer for Mata based on simple economics. Mourinho may have spoken at the time of his desire to do right by the player and give him an opportunity to further his career in the Premier League, but it was the money on offer that turned his head and those of the Chelsea board.
"[Mata] deserves respect, he deserves to be happy and to play where he wants to play,” said Mourinho, as per Sam Wallace of The Independent.
Of course he did, just as Chelsea deserved to receive a considerable profit on their investment for a vastly talented player.
Emotions aside, the deal suited everyone. Mata is playing regularly once more, David Moyes has the marquee signing he has craved since taking over from Sir Alex Ferguson and Chelsea are sitting pretty with £14.1 million profit in the bank.
Had a team on the continent offered more for Mata, the respect Mourinho spoke of would have vanished in an instant. The Spaniard wouldn't have moved to Old Trafford but rather would have swiftly added another stamp to his passport.
Why should it be any different with Oscar? It's not as if he isn't replaceable.
Chelsea have the likes of 20-year-old Lucas Piazon coming through—a player who by all accounts is maturing well while on loan in Holland with Vitesse Arnhem—plus a host of other youngsters in Oscar's position, desperate for an opportunity to prove they are capable of being regulars at Stamford Bridge.
The club's emerging talent is not even the point, though. With the funds Oscar's sale would generate, Chelsea can continue to build, with Eden Hazard becoming even more integral than he already has been this term.
Not so long ago Chelsea allowed Arjen Robben, one of the finest midfielders of his generation, to leave for Real Madrid. The Blues doubled their investment on the Dutch ace, selling Robben for £24 million.
Despite all his talent, Chelsea have more than coped without him.
Similar to Janaury's transfer window, if Chelsea offloads Oscar amid this rumored interest, a portion of his fee will be reinvested while the club uses the remaining funds to push the business forward in these times of Financial Fair Play.
In the most traditional sense, football is a game loved by millions across the globe for the passion it ignites. But as upsetting as it may be, in the modern era finance drives football, and every successful club needs significant funds to survive—sugar-daddy owner or not.
If PSG or any other club comes forward with the right offer for Oscar this summer, Chelsea will be right to see it through.
Garry Hayes is Bleacher Report's lead Chelsea correspondent and will be following the club from a London base throughout the 2013-14 season. Follow him on Twitter here @garryhayes.