Having finished runners-up to Barcelona in La Liga and being ousted from the Champions League at the round of 16 stage by Juventus, Atlético Madrid are set for a huge re-build this summer.
Los Rojiblancos have already signed defender Felipe and look set to confirm the signing of midfielder Hector Herrera in the coming weeks.
New signings are undoubtedly necessary, as the club are set to lose a number of their key players this summer. With Antoine Griezmann requesting to leave, club captain Diego Godín signing for Inter, and Juanfran leaving at the expiration of his contract, Atleti need to replace a number of stars.
So who could Simeone look to bring in to fill the gaps?
It may seem unlikely that the Spanish giants seal a deal for the highly-rated youngster who has attracted interest from both Manchester clubs, Liverpool and Juventus. But with Griezmann set to depart, Simeone will have money to spend.
Felix, 19, no doubt has a bright future ahead of him, and by signing for Atlético he could be an opportunity to star for one of Europe's most competitive outfits.
Despite his €120m release clause, sporting director Andrea Berta is said to be keen to sign the youngster, but knows he must act fast to beat some of the other top sides in Europe to the attacker's signature.
Simeone is keen on Oyarzabal, despite his €75m release clause. The Spanish international netted 14 goals and contributed four assists in 41 appearances in all competitions last season. A player who knows where the goal is, he was the top scorer at the San Sebastian club.
At 22, the left winger - who can also operate as a striker - has plenty to offer and would be given the freedom to develop further under the Argentine boss.
Players such as as Xabi Alonso, Griezmann, Iñigo Martínez, Asier Illarramendi and Álvaro Odriozola have all graduated from the the Sociedad Academy, and Oyarzabal is seemingly the next star on this conveyor belt.
The Ajax left-back could be brought in as a replacement for Filipe Luís or Lucas Hernandez (who has joined Bayern Munich). The 26-year-old helped Ajax to the semi-finals of the UEFA Champions League while also being a consistent performer throughout his side's Eredivise title-winning campaign.
Also a target for Arsenal and Barcelona, there is plenty of competition for his signature.
The Argentinian international, made the most interceptions per game of any Ajax player last season, and has consistently clocked up around three tackles per game over his entire career. A sure-fire star wherever he ends up.
With Godín moving to Inter, Atlético are on the look out for a ready made replacement and could strike a deal for the 22-year-old. Simeone's side would have to pay the €60m release clause of highly-rated Benfica centre-back Dias if they were to sign the Nations League star.
The Spanish giants have already raided the Lisbon-based club back in 2014, having signed goalkeeper Jan Oblak for €16m. They may return this time around for Dias.
Represented by super agent Jorge Mendes, Dias made 55 appearances for the Portuguese giants last season, netting four goals. He could be the perfect long-term replacement for the outgoing Godin.
The 25-year-old right-back is said to be considering his future at the Camp Nou. Simeone's side are on the look out for a new right-back as they seek a long-term replacement for Juanfran, and Semedo could be the perfect option.
He wouldn't come on the cheap though, with the Catalan giants demanding a fee in the region of €40m for secure his services. The Portuguese international could be persuaded to make the move to the Spanish capital, as he would likely be guaranteed more game time.