The full-back was carried off on a stretcher in the closing stages of Barca's 6-0 victory after falling awkwardly under a challenge from Theo Hernandez.
Television replays suggested that Vidal may well have suffered significant damage to his right ankle, and head coach Luis Enrique confirmed after the match that the problem looked to be "serious".
Barca said via their official Twitter account that Vidal "will stay the night in Vitoria and return to Barcelona tomorrow [Sunday]". He is understood to have been taken to the San Jose de Vitoria hospital for treatment.
The incident soured what had been a highly clinical display from Barca, with a double from Luis Suarez, strikes from Neymar, Lionel Messi and Ivan Rakitic and an own goal from Alexis giving them an emphatic win.
Theo later posted on his own Twitter account to offer his apologies to Vidal, although he had won the ball cleanly before the Barca defender accidentally trapped his foot beneath him.
"I'm very sorry for Aleix's injury," the 19-year-old wrote. "I wish him a quick recovery.
"It was an involuntary action. It's always sad to see an injury to a fellow professional."