In the aftermath of Sunday 's derby disaster the talk among fans was of summer incomings to reboot a blue machine that , all-of-a-sudden , looks as outdated as a Commodore 64 . Then there is the inevitable speculation over the future of under-fire manager Manuel Pellegrini . But the biggest challenge for Manchester City this summer could be keeping hold of something they already have . Manchester City risk losing star man Sergio Aguero should they slip out of the Premier League 's top four . Aguero scores the first of his two goals during City 's 4-2 defeat at the hands of rivals Manchester United . It may have gone largely unnoticed in the carnage at Old Trafford but there was an important landmark for the brilliant Sergio Aguero that deserves to be recognised . The aftermath of a crushing derby defeat at the old enemy may not be the place for jelly and ice-cream but the Argentine 's tremendous feat of scoring 100 goals in just 158 appearances should be cause for celebration . Take a minute to think where City would have been without that century . Remember THAT title-winning goal against QPR in 2012 ? Most , in that situation , would have put their foot through the ball as soon as it arrived from Mario Balotelli . The Argentine forward clinched the Premier League title for City with this striker against QPR in 2012 . Aguero wheels away in celebration after giving the City faithful inside the Etihad a moment to remember . Not Kun . The man who takes his nickname from a cartoon character had City fans believing in fairy tales when he feigned a shot to open up space before firing home probably the biggest goal in the club 's long history . That calm head , that powerful shot and that unnerving ability to find the target are what City paid what now looks like a bargain £38m for in 2011 . Aguero is settled in Manchester and signed a new five-year deal only last August . However , he now has to think of himself . Aguero scores past United goalkeeper David de Gea to earn his 19th Premier League goal of the season . The City players look dejected during the 4-2 defeat which left their side fourth in the Premier League table . If the unthinkable happens and City slip outside the top four will one of the best players in the world be happy at a season without showcasing his talents on the Champions League stage ? There are admirers . Real Madrid and Barcelona are both fans . Should either register an interest City would face a desperate battle to keep hold of their star man . While a move to Madrid may come with an enticing caveat in the shape of Gareth Bale , the loss of Aguero would be exceptionally difficult to recover from . Manuel Pellegrini signed former Swansea City striker Wilfried Bony for £30million in January . April 19 West Ham United ( H ) April 25 Aston Villa ( H ) May 3 Tottenham Hotspur ( A ) May 10 Queens Park Rangers ( H ) May 17 Swansea City ( A ) May 24 Southampton ( H ) Where else do you get those goals from ? While it is too early in his City career to pass judgement it would appear that the burden would be too much for Wilfried Bony 's broad shoulders . The former Swansea City man , who cost just £10m less than Aguero , has failed to hit the ground running since his January move and has scored only once in five appearances . The powers-that-be would no doubt have to open their chequebook but who would come to an Aguero-less City ? And , should they sleepwalk out of the top four , who would dream of coming to a club without Champions League football ? City are reportedly targeting Juventus midfielder Paul Pogba as they look to strengthen this summer . The likes of Paul Pogba and Raheem Sterling are potential targets . Sportsmail understands discussions have already taken place with a number of new additions . But will they also want to come to a club shorn of its idol ? It is a big question and one that City will be desperate not to have to discover the answer to . There are others to ponder . Does Pellegrini stay ? And what share of the blame do executives Ferran Soriano and Txiki Begiristain take ? Pellegrini 's future as City boss is in doubt after a difficult 2014-15 campaign at the Etihad . Are they at fault for spending the best part of £200m since 2012 without really strengthening the team or does Pellegrini carry the can ? With Financial Fair Play sanctions hurting , it was essential that City got bang for the buck . In reality they barely had a whimper . The pile on the in-tray on chairman Khaldoon al Mubarak 's desk seems to be getting taller every week . It is essential that keeping Aguero is top of that ever-growing list or else that ageing blue machine risks heading for an even bigger crash .
Manchester City have slipped to fourth in the Premier league table . manager Aguero may look elsewhere whilst they continue to struggle . Argentine striker has scored 19 Premier League goals so far this season . Manuel Pellegrini 's future as City striker is also in doubt . Real Madrid and Barcelona are both fans of the former flame Madrid star .