Lionel Messi may have to miss Barcelona’s opening Champions League match against Celtic next week due to a groin injury.

Messi returned to international football with Argentina last week and during the game he aggravated the injury. However, he also scored the winner in the team’s World Cup qualifying match against Uruguay.

Messi, who has five times been voted World Player of the Year, was due to play in Argentina’s next qualifying game against Venezuela last Tuesday but instead he had to return to Catalonia where he had a number of scans over the weekend.

After the scans Barcelona released a statement which said that after the tests had been carried out it become apparent that he is “still having trouble with the left adductor muscle.”

The statement went on to say that Messi has been recommended by doctors to lighten his training load over the coming days and as a result his availability for matches is uncertain.

However, Messi has been playing down the injury and wrote a Facebook post saying, “Everything is fine, I have to slow things down as I recover with physio, but it’s nothing to worry about.”

According to the Argentina manager Edgardo Bauza, Messi’s decision to play in the match against Uruguay was against the wishes of Barcelona’s doctors.

His appearance for the team was a dramatic reversal of his decision from earlier in the summer to retire from international football following the team’s defeat in the Copa America final to Chile. He said that he loves Argentina “too much” to leave the national team and he is now hoping to win some trophies with the team, something he is yet to do.

Barcelona play Alaves in La Liga this weekend before hosting Celtic in their Group C opener on Tuesday.