The Spaniards have had the Belgian number one on loan from Chelsea for three successive seasons, but look set to lose him this summer amid talk that Jose Mourinho wants him back in London for next season.
As a result they are pondering a list of targets, and Krul is thought to be at the top.
The club are rumoured to have been impressed by his consistent displays for the Magpies, and have been buoyed by recent rumours that he is ready to leave St James’ Park in search of Champions League football.
Atletico sporting director Jose Camacho is thought to have been in attendance at the Emirates Stadium on Monday night to watch the Dutchman, and was encouraged by his display despite Newcastle’s 3-0 loss.
A bid of around £10m for the 26-year-old is being considered in the Spanish capital, which could be funded by their impressive run to this season’s Champions League semi-final.
Krul has just two years on his contract, which may tempt the Tynesiders to sell now rather than watch his value deplete.