Per the source, Mathieu was replaced at the end of the first half due to a hamstring problem in his right leg.
The French defender was replaced by summer signing Lucas Digne and Barca went onto win the game 1-0.
Mathieu is expected to miss the next three weeks which could result in Arsenal cooling interest in the defender.
Arsenal made an enquiry for Barcelona defender according to the Evening Standard.
The Gunners are in desperate need of defensive reinforcement after Per Mertesacker, Gabriel and Koscielny were ruled out of the opening Premier League game of the season which the North London based outfit lost 4-3 against Liverpool at the Emirates.