Arsenal coach Mikel Arteta said young attacking midfielder Ethan Nwaneri will be sidelined for a few weeks due to a muscle problem.
The 17-year-old came off at the end of the first half Saturday tied with Brighton 1-1 After scoring the opening goal of the match.
The England Under-19 international made his Premier League debut three days ago, during Arsenal's 3-1 win over Brentford.
“Unfortunately, he suffered an injury and will be out for a few weeks,” Arteta said on Monday.
Nwaniri achieved a major achievement with the first team this season, as he scored his fifth goal in 18 matches on Saturday.
He enjoyed more playing time after A.J Bukayo Saka injured his hamstring Which will keep the influential England winger out of the field for “several weeks.”
Regarding Nwaniri’s injury, Arteta added: “He didn’t really know, to be fair. He said: ‘I feel something but I don’t really know what it is.’”
“He's earned the right to step up and play for us, and now he's started some games – some big games – and affected those games the way he has, in different positions as well.
“I'm sad for him because the injury will stop that, but it's another step in his development. I'm really happy with the way he's going.”
Raheem Sterling was also injured days before Saka, and Arteta said the on-loan Chelsea striker would return “hopefully very soon”.