Wolverhampton Wanderers striker Sasa Kalajdzic (25) sustained a knee ligament injury on his debut for the Premier League club, they said on Sunday.
The Austrian was substituted at halftime of Wolves' win over Southampton on Saturday.
"Sasa felt a pain in his knee late in the first half... Unfortunately, scans reveal an anterior cruciate injury and he will see a knee specialist tomorrow," Wolves wrote on their website.
Mexico forward Raul Jimenez was withdrawn from the squad before kick-off.
"Raul's pre-season was interrupted by a knee injury which means that he is still building his resilience," Wolves said.
"It was felt that his body needed a few more days to recover after he felt a pain in his groin during the warm-up and we did not want to put him at increased risk of injury."