Ousmane Dembele went AWOL after vanishing for an hour and a half on Thursday morning.
The Frenchman did not notify Barca that he would miss training on Thursday due to gastroenteritis, and will now face questions after the weekend fixture with Betis.
The 21-year-old has found life tough at Barca, but his form this season has vastly improved.
Reports in RAC1 and Mundo Deportivo claim that Barca officials were attempted to call the former Borussia Dortmund winger but he did not return their call for 90 minutes.
The incident is said to have caused unrest with boss Ernesto Valverde, who has warned the youngster about turning up late to training in the past.
Dembele is now expected to lose his place in the Barca squad for Saturday to Malcom, who scored against Roma on Tuesday.
Barcelona striker Luis Suarez has been named La Liga’s best player of October.
The Uruguayan hit four goals last month, including a sublime hat-trick in the 5-1 win over Real Madrid in El Clasico.
The 31-year-old becomes the second Barcelona player to win the award this term after Lionel Messi was named September’s best player.
Suarez will be presented with the award in front of the Camp Nou on Sunday as Barca host Real Betis.