The forward appears set to miss his team’s league opener at Bilbao, with Valverde saying it’s hard to see the star returning for the clash.
“He’s in the recovery process and I don’t know if he will be ready for the start of La Liga,” he told a news conference after a 4-0 win over Napoli in Michigan on Saturday.
Should Messi miss the clash against Athletic, he will look towards an August 25 match against Real Betis to potentially make his season debut.
Despite Messi’s absence, Barca produced a strong performance in their final pre-season friendly against Napoli.
Antoine Griezmann scored his first goal for the club, Luis Suarez netted a brace and Ousmane Dembele was also on the score-sheet in a comfortable win.
Valverde was pleased to see Griezmann, who arrived from Atletico Madrid for €120 million in July, get off the mark for Barca.
“Goalscorers are always boosted by the chances they get, by goals… it’s good for them to have a good relationship with the goal,” Valverde said of the France star.
“He had clear chances to score earlier, too. I am happy that all the forwards scored, including him, above all because he gives us a lot in attack with his movement.
“It’s positive to see how he’s playing.”
