Rabiot, 22, has a deal which runs until the summer of 2019 but it does not reflect his value to the Ligue 1 leaders because it was signed while Laurent Blanc was still coach and before he blossomed into a regular member of Unai Emery's starting XI.

According to the source, PSG have been keen to tie the France international down to an improved contract for the past few months.

However Rabiot and his mother, Veronique, who is also his agent, initially resisted the temptation to extend his stay at Parc des Princes because they were unconvinced about the direction Les Parisiens' project was headed at the time and wanted guarantees that he was not going to be moulded into Thiago Motta's heir in the deep-lying midfield role.

The source explained that Rabiot and his mum have been impressed by PSG's actions in recent months, notably the signings of Neymar and Kylian Mbappe, as well as the appointment of Antero Henrique as sporting director in place of former incumbent Olivier Letang and ex-director of football Patrick Kluivert.

However, despite recent reports in France suggesting that a deal until 2021 with an option for an additional year is imminent, the source indicated that it is still a work in progress.

Rabiot has scored two goals and provided three assists from 17 appearances across all competitions so far this season and has split his time between Motta's deep-lying role -- when the veteran Italian has been unavailable -- and a more advanced left-sided central midfield berth, which he favours.

The source also told ESPN FC that PSG are working hard to find new clubs for unwanted trio Lucas Moura, Javier Pastore and Hatem Ben Arfa, while also looking for a new defensive midfielder.

Inter Milan's Joao Mario has been linked and the source said that the Portugal international is one of the players Henrique has been looking closest at and the fact he is currently out of the starting XI under Luciano Spalletti could work in PSG's favour.

Inter have shown an interest in Lucas in the past, while Mario is a similarly peripheral figure for the Nerazzurri. The source said a swap deal involving Lucas or Pastore could be considered and Mario himself did not rule out a potential January move when speaking at a news conference ahead of Portugal's friendly with Saudi Arabia on Friday.

"I cannot do anything but obviously I would like to play more, like many others in my position," said Mario. "I think things can change and that's what I am focusing most on. One way or another, I will play more, so I am not worried.

"PSG? Rumours are normal and part of football. I always stay focused. I do not want to get distracted because I am used to that sort of thing.

"We will see. I think it is still early and there is still a long time until the transfer window opens again. We will see what is going to happen and I will make a decision on what is best for my career."