Bolton Wanderers striker Max Clayton has been ruled out for up to six months after surgery on the anterior cruciate ligament in his right knee.
The 20-year-old moved to the Macron Stadium from Crewe in the summer for a compensation fee of around £300,000.
Clayton has featured regularly since Neil Lennon became boss, and scored in last month's derby win over Wigan.
He is the second striker Wanderers have lost this week following Joe Mason's hamstring tear.
"It's a clean cruciate if you want to call it that, where there's no complications with it," Lennon, 43, told BBC Radio Manchester.
"He's a fit young lad so you are looking at maybe six months, which seems a lifetime away, but hopefully for him it will go quickly and we'll have him for the start of next season.
"It's a blow to us because he was playing very well, and it's a blow to the lad to get to the form he was in."
Clayton scored 16 goals in 92 appearances for hometown club Crewe after coming through their academy.
But he rejected a new contract and after training with Sunderland and Wolves during the summer, he agreed a three-year deal at Bolton.
Meanwhile, manager Lennon has confirmed they will further assess former England striker Emile Heskey, who is on trial at the club, on Monday when he plays in a Under-21 match.