This will be Atleticos first Champions League campaign without old star forward Antoine Griezmann since the 2013/14 season, following the World Cup winners high profile summer move to Los Colchoneros La Liga title rivals Barcelona.
During the Frenchmans five years at the club, Atletico reached a final, a semi final, a quarter final and a round of 32. There was a year when they failed to make the knockout stages, but made up for it by winning the Europa League that season.
And while Atleti pocketed €120m from Griezmanns sale and reinvested the cash into the signings of Joao Felix, Marcos Llorente and Kieran Trippier among others, there is reason to be worried ahead of this new campaign in the Champions League.
When you look closely at Los Colchoneros recent Champions League record, it is very clear that one player has been integral to their success - and that player is Griezmann. The 28-year-old forward scored or assisted a staggering 54% of Atleticos goals in Europes elite club competition, helping himself to 19 goals and seven assists since September 2015.
Atleti manager Diego Simeone is renowned for his defensive excellence, which has made the Spanish side known for their solidity at the back and their ability to beat opponents through quick counter charges.
Griezmann blossomed in this system, as his pace, vision and deadly execution provided the missing pieces of the puzzle. With the Frenchmans world class abilities, Atleticos stern defence could restrict the best attacking teams on the toughest nights in European football, whilst swiftly countering through Griezmann and bagging the goals themselves, and usually doing so by having only a smidge of possession.
Now that Griezmann has left the club, a few fans might question where Atleticos goals are going to come from against the elite clubs in Europe.
Truth be told, Atletico were already a European powerhouse prior to Griezmanns arrival. The season before the Frenchman arrived at the club, Atletico lost a narrowly contested Champions League final to fierce rivals Real Madrid in a match that finished 4-1 after extra time.
Joao Felix, the 19-year-old Portuguese wonderkid and one of the most highly rated young players out there, was snapped up by Atletico as a direct replacement for Griezmann in a €126m deal this summer. It is too early to tell whether he will be as influential as the Frenchman for Simeones side, but the early signs seem to suggest that he could well be.
In his first three La Liga matches, Felix has already bagged himself a goal and an assist for his new employers. Furthermore, lets not forget his man of the match performance in a 7-3 hammering against Real Madrid earlier in pre-season, where he scored a goal and set up two for his teammates.
Griezmanns departure will definitely be felt by Los Colchoneros supporters, but it is important to remember that Griezmann was probably made at Atletico, under the European floodlights, not the other way around.
Theres no reason why Felix cant do the same on the European stage.