Dele Alli sustained a minor thigh strain in England's World Cup opener against Tunisia, the Football Association has confirmed.
The 22-year-old helped Gareth Southgate's men to a 2-1 victory in Volgograd on Monday, when he looked set to come off in the first half after suffering a knock.
Fabian Delph was stripped and seemingly ready to come on, but Alli managed 80 minutes before eventually being replaced.
The England midfielder went for a scan as his team-mates trained on Tuesday afternoon and the FA has confirmed the assessment showed a minor thigh strain that will need managing over the coming days.
Before travelling back to Repino on the outskirts of St Petersburg, Alli spoke of his hope that it would not be a problem for Sunday's Group G encounter against Panama and beyond.
"Hopefully I am OK," he said after the game. "It's my quad."
England manager Southgate had kept tabs on Alli's fitness throughout their World Cup opener after the first-half setback.
"We had to keep monitoring Dele," the Three Lions boss said on Monday.
"He was feeling a little bit of an issue just before half-time, but he felt he could carry on and I thought the runs that he was making and the way he was pressing the ball was still causing a problem.
"He had a half chance with a lovely ball Jordan Henderson played to him, lofted over the top.
"But we have good options on the bench and we felt to put the freshness of Marcus (Rashford) and Ruben (Loftus-Cheek) would both bring fresh energy but also a different sort of threat to the one that we'd posed."
Alli's thigh strain was the only injury setback on a long night for England, who did not make it back to Repino until the early hours of Tuesday morning.
The substitutes against Tunisia participated in a training session that afternoon, while the starters did some gym work.
Meanwhile, England's wing men Kieran Trippier and Ashley Young are confident there is enough firepower in the side to share the scoring burden if Harry Kane's hot streak ever cools down.
"If Harry doesn't score we've got players who can," said Tripper.
"We're one team over here and we know we've got quality all over the pitch. We've got Marcus Rashford, Raheem, Dele, Ruben (Loftus-Cheek), they've had fine seasons, Jesse has as well...Vards (Jamie Vardy).
"They've had excellent seasons for their clubs and hopefully in this tournament they can provide some for us."
Young, fresh from his first World Cup appearance at the age of 32, was singing from the same hymn sheet.
"I think you need goals from all over the pitch and I think that's what we'll be looking to do," he said.
"You want a major goalscorer, a striker that's going to take chances, but we've got that in abundance around the team with Vards, Welbs (Danny Welbeck) and the kid Rashford.
"It's not just the strikers, it's the midfielders as well. We saw Jesse had a few chances, Raz (Sterling) had a few chances as well. There's plenty of goals I've seen all over this team and I think if everyone's chipping in and pulling in the same direction it just sets us up right for the next game."
