Leo Baptistao and David Villa have both arrived in the striking department this summer, while Belgian goalkeeper Thibaut Courtois has re-joined on loan from Chelsea and experienced defender Martin Demichelis has added steel to the back four.
That said, Barcelona and Real Madrid have also added new personnel to their squads this summer, while Simeone will have to do without his top scorer from the last two seasons Radamel Falcao, who agreed to join big-spending Monaco.
Here, Sports Mole selects five players that could help Atletico upset the top two in Spain next season.
Patrick Ebert (Real Valladolid)
The 26-year-old will not be a name too readily recognised, but the fact of the matter is that he is one of the most talented midfielders in La Liga.
The Real Valladolid winger spent a large part of last season on the sidelines due to injury, but he showed flashes of brilliance during his time on the pitch.
The German has indeed been widely linked with a move to Atletico in recent months, but thus far a transfer fee has not been agreed between the two clubs.
Ebert, who primarily operates on the left of midfield, demonstrated his ability from dead-ball situations last season, in addition to displaying a keen eye for a pass.
A number of clubs have been credited with an interest in the former Hertha BSC star since the end of the season, but with Ebert keen to remain in La Liga, a chance to turn out at the top level for Atletico could seem too good an opportunity to miss.
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Christian Benteke (Aston Villa)
Much has been said about the 22-year-old in recent weeks, with the Belgian recently handing in a transfer request at Aston Villa, who he joined from Genk last summer.
His 19 goals in the Premier League last season kept Villa in the division, while also drawing the attention from a number of clubs, both at home and abroad.
Chelsea, Tottenham Hotspur and Arsenal have all been linked with Benteke's services in recent weeks, who has reportedly been valued in the region of £30m by Villa boss Paul Lambert.
Atletico have money in the bank following the sale of Falcao, and despite acquiring Villa and Baptistao this summer, there is certainly room in their squad for one of the best young talents in European football.
With Villa seemingly unprepared to sanction a move to one of their Premier League rivals, a late move from Atletico could be enough to secure the Belgian's services for the new La Liga season.
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Samir Nasri (Manchester City)
It wasn't too difficult to notice that the Frenchman struggled at Manchester City last season with Roberto Mancini continually playing the 26-year-old out of position.
Nasri's temperament and off-the-field behaviour have left much to be desired at times during his career, but his ability on the football pitch cannot be questioned.
City only acquired the Frenchman from Arsenal in 2011, but it is understood that the playmaker will be available for the right price, with a number of midfielders arriving at the former Premier League champions this summer.
Nasri is said to be open to a move to Spain, but it is unlikely that either Barcelona or Real Madrid will make a move for his services having both already spent big this summer.
Champions League football would be on offer at Atletico, while Simeone could see the chance to sign one of the best playmakers in Europe too good an opportunity to turn down as the Argentine looks to create a squad capable of challenging at home and abroad.
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Ivan Rakitic (Sevilla)
With eight goals and 10 assists to his name in La Liga last season, it is not too difficult to see why the Croatian midfielder has been linked with a number of European outfits this summer.
The 25-year-old, who struck 11 times in all competitions, has recently indicated that he would be prepared to depart Sevilla should the Spanish outfit fail to properly invest in their squad this summer.
His ability to perform in a number of midfield areas would also prove a desirable option for Atletico, with Rakitic capable of operating behind a front man, or as a deep playmaker in front of the defence.
There is no question that Sevilla are a big side, not only in terms of Spain, but in terms of European football, but a player of Rakitic's ability should be gracing the biggest of stages – something which Atletico could provide next season.
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Aleksandar Kolarov (Manchester City)
The 27-year-old has been a steady operator for the Premier League side since joining from Italian outfit Lazio in 2010, with the Serbian impressing in a number of positions.
However, it proved to be a disappointing campaign for the left-back last season, with Gael Clichy preferred in defence by former boss Mancini in the latter stages of his tenure.
It is understood that new City boss Manuel Pellegrini wants to keep Kolarov at the club, but the chance to play regular Champions League football could turn the defender's head.
Felipe Luis would hardly welcome the acquisition of a rival left-back, but Kolarov's ability to operate as a wide midfielder could prove a serious attraction for Simeone.
Should City decide to sell, it is unlikely that they would ask for big money for the defender, which would make the signing even more attractive to the Spanish outfit.
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