Felix opted to undergo an operation on a persistent ankle problem following Portugal’s exit from Euro 2020 this summer.
However, the 21-year-old has suffered setbacks on his comeback trail in recent weeks, with Diego Simeone forced to begin the 2021/22 campaign without him.
According to reports from Diario AS, the former Benfica star has now returned to full training after being omitted from international duty this month.
Felix’s return to first team action could now be mirrored by a second club debut for Antoine Griezmann following the Frenchman’s dramatic deadline day return to Madrid.
Griezmann has already joined up with the France squad for their 2022 World Cup qualifiers this week but he is expected to go straight into Simeone’s plans this month.
Los Rojiblancos return to action on September 12 with a trip to Espanyol ahead of their Champions League kick off at home to Porto.