Barcelona midfielder Pedri will face a spell on the sidelines because of a left hamstring injury, his club said on Wednesday.
Pedri has played 41 consecutive competitive games for Barça but sources have told ESPN he is expected to be sidelined for several weeks and will not return until at least after the international break.
He was sent off in the 10th minute of added time in the Clásico after being shown a second yellow card for a foul on Aurélien Tchouaméni.
The Spain international played all 90 minutes of his team's 2-1 league loss at Real Madrid in Sunday's Clásico.
"First team player Pedri has suffered a tear in the distal biceps femoris muscle in his left thigh," the club said in a statement.
Barcelona take on Elche on Sunday before their Champions League game at Club Brugge on Nov. 5. They visit Celta Vigo before the November international break.
However, Barça coach Hansi Flick did receive some good news with Robert Lewandowski and Dani Olmo rejoining the group in Wednesday's training session.
Both players picked up injuries during international window in October.
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