MADRID, Aug 5 (Reuters) - In a bombshell development, Barcelona announced on Thursday that superstar and six-time Ballon d"Or winner Lionel Messi would leave the club after 18 years. The Catalan side said that financial regulations imposed by La Liga would prevent them from retaining their highest-ever goalscorer, which begs the question: what next for Messi? MANCHESTER CITY When Messi asked to leave Barca in summer 2020, he was expected to link up with former coach Pep Guardiola in Manchester. However, with City looking like they have moved on, signing playmaker Jack Grealish and reports linking them with Tottenham Hotspur striker Harry Kane, this avenue seems closed to the Argentine. The Abu Dhabi controlled owners of City have deep pockets, though, and might see this as an opportunity that is too good to miss. PARIS ST GERMAIN Perhaps the most likely move abroad. One of the few clubs in world football who could afford his wages, PSG have been linked with moves for Messi ever since they were taken over by Qatari Sports Investments in 2011. With fellow countryman Mauricio Pochettino at the helm of the Ligue 1 side, former team mate and close friend Neymar and the electric Kylian Mbappe as potential strike partners, Messi might well prove the missing piece of the jigsaw in their quest to finally win the Champions League. STAYING AT BARCELONA Some observers believe this announcement to be a major calling of La Liga"s bluff from Barca. They say the best player in the world will leave the league because of league-imposed constraints in a bid to get La Liga to loosen their financial fair play (FFP) regulations to allow him to stay. If that is the case, it is a bold move, with league chief Javier Tebas having frequently criticised the club"s financial situation and recently repeating that they need to drastically reduce their wage bill in order to retain Messi. Whatever the outcome, it allows them to absolve themselves of responsibility in their fans" eyes over the whole situation.