José Mourinho, head coach of Fenerbahçe, one of Turkey's most successful clubs, suffered a minor knee injury on Thursday after an unexpected collision with midfielder Ismail Yüksek during training.

While preparing his team for their upcoming match against Trabzonspor this Sunday, Mourinho was inadvertently pushed from behind by Yüksek as the player rushed toward the ball just as Mourinho was turning. The unexpected nudge caused the Portuguese coach to fall, and medical staff and club officials quickly assisted him off the field.

Reports from Turkish outlet NTV confirmed that Mourinho sustained a knee injury but assured fans it’s not serious.

Mourinho later commented on the incident with humor on his Instagram account, writing, “Lesson for young coaches: never dress in the same color as the players. You might get passed the ball… or a hit from behind.”

Fenerbahçe currently sits third in the Turkish Super Lig, eight points behind their traditional rivals, Galatasaray.