Canadian teenager Denis Shapovalov has withdrawn from next week's Next Gen ATP Finals in Milan because of exhaustion, organizers confirmed on Wednesday.
Shapovalov who qualified for the second year running, will be replaced by Polish player Hubert Hurkacz.
The 19-year-old is ranked 29th in the world after an impressive second year on the ATP Tour.
The Next Gen Finals features the top eight players aged 21 and under, although Germany's Alexander Zverev will also be missing as he has qualified for the ATP World Tour Finals.
Denis Shapovalov withdraws from Next Gen Finals