Jamie Vardy suffered a groin strain during England's win over Colombia and is now doubtful for the upcoming quarter-final against Sweden, Sky sources understand.
Second-half substitute Vardy was due to take England's fifth penalty in the dramatic shootout on Tuesday night but was unable to do so, with Eric Dier taking and scoring the decisive spot-kick instead.
Sky sources understand Vardy had an injection on the injury after the match but remains a doubt for the quarter-final in Samara on Saturday.
"Dier wasn't supposed to take that decisive fifth penalty," Sky Sports News'Rob Dorsett said.
"Vardy, the man who takes penalties regularly for Leicester, was down to take it but he picked up a groin strain towards the very end of extra-time so massive credit to Dier."
While Vardy will continue to be monitored, Gareth Southgate also faces an anxious wait over the fitness of Tottenham duo Dele Alli and Harry Kane.
Alli looked to be troubled by the thigh problem which had previously ruled him out of the games against Panama and Belgium, while Kane was seen holding his back during the match.
Ashley Young and Kyle Walker also appeared to suffer cramp towards the end of the win over Colombia and boss Southgate admitted the match took its toll on his side.
"It's like a scene from M*A*S*H in the dressing room," he said post-match.
"Some just cramp, and some need just a little bit more assessment, so we'll know more over the next 36 hours."
"I thought there were many, many fouls in the game and I don't think we conceded anywhere near the number of our opponents."
Dier praised the mental resolve of his team-mates after Yerry Mina had dramatically forced extra-time with a 93rd-minute header but admitted to nerves before his decisive spot-kick.
"It was a nervous one."
"I've never really been in a situation like that before but felt I had to score after missing a header at the end so I'm just thankful I scored," the Tottenham player said.
"To get knocked down like we did is difficult to come back from it."
"But we knew what we had to do and we stayed calm."
"We never panicked."
"We were ready for that."
Source: Skysports