After submitting an initial bid of €21 million for Callejón at the start of the summer, it looks like Atlético may be preparing a fresh second offer.
If reports in Italy are to be believed, Callejón's relationship with manager Rafa Benítez is becoming increasingly strained as the Italian club prepare for the new season.
Callejón was one of Napoli's most important players last season, arriving from Real Madrid for €10 million during the pre-season of 2013. The winger went on to score 17 goals in his debut Serie A season and became a fans favourite at the Stadio San Paolo.
Sky Sport Italia claimed yesterday that Benítez ordered the winger to leave their morning training session, claiming his attitude and effort was not up to par. The Spaniard was seen leaving the field shortly after, clearly riled by the order given by his manager.
If a revised offer from Atlético were to arrive in the near future, it seems likely that Callejón would be open to a move back to his native Spain. Diego Simeone is said to be a keen admirer of the winger's versatility and quality.
The winger is a product of Real Madrid's youth setup and also appeared for the first team three years after being let go by the European Champions. A possible move to Atlético would not go down well among their city rivals Los Blancos.