BARCELONA, SPAIN - SEPTEMBER 21: Lionel Messi of FC Barcelona reacts injured on the pitch during the La Liga match between FC Barcelona and Club Atletico de Madrid at the Camp Nou stadium on September 21, 2016 in Barcelona, Spain. (Photo by David Ramos/Getty Images)

Argentinian sensation Lionel Messi has reportedly told newly appointed coach Ronald Koeman that he has doubts about staying in Barcelona following the club’s humiliating Champions League campaign.

Barcelona labelled the club legend as ‘untransferable’ as European giants continue to circle the star forward.

Messi reportedly told Koeman he is ‘more out than in’ at Barcelona with Pep Guardiola’s Manchester City the favourite to snap him up should he become available.

He is also being monitored by Paris Saint-Germain, Inter Milan and Juventus, according to Spanish news outlet, Sport.

Messi has one year left on his contract and a release clause worth more than $1bn.