The Young star Sergio Leonel Agüero del Castillo, has privately indicated "yes" to a move that will make him one of the highest paid players in the world, with a transfer fee that will smash the British record of £32.5m for Robinho by some distance.
Chelsea almost signed the boy who is engaged to Diego Maradona's daughter, Giannina, with whom he has a son, in the summer, but the deal broke down over the players £6m-a-year wage demands on top of Atletico demanding a £60m transfer fee.
However The Blues know they have to meet the player's wage demands to make a spectacular signing in the January window while their FIFA ban is still suspended.
Talks have been on-going for several weeks between a host of middlemen intent on making the deal happen, and there is now room for optimism that it will advance sufficiently in the next four weeks to be in a position for the move to take place in January.
ESPN Soccernet has been told by one of the insiders involved with the deal that there is far more flexibility on all sides than there was been in the summer when the deal broke down.
My source revealed: "There is still more talking to do, but let's see. There is now a possibility, although with so many complications involved you would have to say it's still 50-50 whether it will finally go though."
Chelsea are keen to capture one of the best young players in world football at a time when their transfer ban has been suspended pending a FIFA hearing. They urgently need to make significant signings at a time when the big clubs usually only make interim moves and wait for the summer.
Roman Abramovich cannot take the risk of waiting until the end of the season in case Chelsea are banned from making any signings, so needs to act now, and intermediaries have stepped up the process of attempting to bring Aguero to Chelsea.
The Blues are not as reluctant to invest in Agüero's salary as much as they are about Atletico's asking price of £60 million, which has dropped to £55 million. Talks are aimed at trying to get the fee below £50 million and closer to £40 million.
A compromise of money offered up in relation to Chelsea's success is the logical route to resolve the differences in the transfer fee valuation.
Chelsea would be prepared to hit the £50 million mark, if it included add-ons related to success, given that Real Madrid paid £80 million for Ronaldo, and the Argentine is a few years younger.
Chelsea would ideally like to sign Aguero for six years, but five years is normally regarded as a long-term deal, but as the player is so young at 21, they be might be able to stretch to six years or more, even if the final years are optional.
While Chelsea might start to pay the youngster £6 million-a-year, that will rise quickly to £10 million and that will go even higher in the final year of his deal.
Overall, including bonuses, and given Chelsea's propensity for silverware, he can realistically expect to yield £50 million from his personal terms and image rights, to add to the near £50 million transfer fee, totally an eye watering £100 mllion.
The player's agent Bruno Satin, head of the football division of IMG, one of the world's biggest sports agencies, based in Chiswick in London, is one of a number of agents working on negotiating an acceptable fee with Athletico.
Manchester City are the only club that could possibly compete with Chelsea at this level of transfer, but my source tells me: "The player doesn't want to go there, and Manchester City do have a problem with trying to sing players at this level, as they did with Kaka, because they are not serious yet. They will be, but they are not just yet."
For that reason Atletico have to be realistic to drop their asking price as Chelsea are the only buyers at that kind of price. That's why there is greater optimism of a deal going through than there has been at any other time.
A transfer of £40 million plus a near £10 million add ons based on Chelsea's success during the duration of the players contract would be one of the biggest deals in world football. The entire financial package won't be far short of the Real Madrid deals for Kaka and Cristiano Ronaldo.
My source added: "Money was the problem the deal fell through in the summer, and the money is the problem now, but we shall see, as I said, the talks are on going and everyone seems to want to find a solution."
Chelsea manager Carlo Ancelotti has targeted Agüero as his only major signing during the January transfer window. The club have been given permission to buy and sell after the Fifa-imposed transfer ban, following the Gaël Kakuta affair, was frozen pending an appeal to the Court of Arbitration for Sport.
Agüero scored two spectacular goals during the recent 2-2 draw with Chelsea in the Champions League. After the match Ancelotti joked that he would like to sign the exciting striker. But before that Ancelotti admitted Chelsea have been "monitoring" this player for some time.
Chelsea also remain interested in Bayern Munich's Franck Ribery, who would command a similar hefty investment in fees and salaries, and who is also greatly admired by Ancelotti.
But my source indicates that Ribery will be hard, if not impossible, to prise from Bayern in January, but will be a far more realistic target in the summer, if Chelsea win their appeal with FIFA. Chelsea's determination to secure the Aguero deal as they are aware that if their CAS appeal fails, they cannot make another signing for some time.
Agüero will not be eligible for Chelsea in the Champions League this season, having already played for Atlético, but Abramovich wants to win back the Premier League title from Manchester United, and the club are concerned about losing Didier Drogba and Solomon Kalou to the African Nations in January.
At 15 years and 35 days Aguero beat Maradona's record as the youngest player to make debut in Argentinean top flight. In May 2006, he joined Atlético Madrid for £16m.
He lost his place in the Argentine attack during the chaotic final stages of qualification, and needs to be playing at the highest level to play in the World Cup finals in South Africa, rather than with struggling Athletico, a factor that Maradona has made clear to him, and one of the reasons the player is keen to move to the Bridge.
