Pato signed in January but has yet to feature for Chelsea.
Pato signed for the club on loan from Corinthians for the rest of season back in January but has yet to make an appearance for first team, and has been an unused substitute on two occasions.
It would go down as a very odd signing - if it wasn't already - if the deal were to be cancelled. Chelsea did look a little short of firepower given their reliance on Diego Costa while Loic Remy has never really had a run of games in the side and Radamel Falcao has been on the sidelines for quite some time but is now back in full training and could be ahead of him in the pecking order.
Interim boss Guus Hiddink had spoken of the need for Pato to train and get himself up to speed in a 'pre-season of his own before being considered for selection, but this report indicates that Pato isn't coming into the thinking of the Dutchman right now.
There are just nine games left in Chelsea's season as they were knocked out of both the Champions League and FA Cup in the past week, which limits opportunities for Pato to be handed some regular football.
It seems that Pato's time in London will be brief, whether the loan is cancelled or not, especially given that a new manager is expected to arrive at the club during the summer.