The Argentina international has already scored four goals and four assists in nine games for the Catalan giants this season and his omission comes as a huge blow ahead of their league clash with Betis.
Speaking to Spanish media ahead of the match, Schreuder said: "We're not talking about an injury (for Messi), he's just not fresh.
“He has played a lot of games. Koeman has said: if you're not 100 percent fresh, it's better you start on the bench.”
Despite Barcelona’s wavering form this season and last, Messi’s involvement in the first team was usually a safe assumption.
The attacking midfielder has featured in every minute of his club’s domestic and European campaigns to date and only missed seven of Barcelona’s 51 games last season.
The last time he failed to start a league match for Barcelona was over a year ago, when an adductor injury ruled him out of the club's 2-0 victory over Getafe in September 28, 2019.