Mo Salah had to be subbed off just before half-time in Egypt's 2-2 draw with Ghana at the Africa Cup of Nations on Thursday.
Liverpool forward Salah pulled up after attempting to run and was pictured holding his left hamstring before walking off the field.
Egypt coach Rui Vitoria told reporters after the game: "Of course, we are worried and we hope it is not too serious."
The game was still tied at 0-0 when Salah made his exit, but Ghana took the lead moments later.
West Ham's Mohammed Kudus opened the scoring with a brilliant solo goal when he slammed home a low shot from 23 yards.
Omar Marmoush equalized for Egypt midway through the second half before Kudus struck again to restore Ghana's lead.
But Mostafa Mohamed netted his second goal of the tournament in the 74th minute to earn a 2-2 draw.
Highlights: Egypt 2-2 Ghana
Egypt have now drawn both of their Group B games 2-2.
Salah converted a 97th-minute penalty in a four-goal thriller against Mozambique in Egypt's opening match.
However, it is unclear whether Salah will now be able to play against Cape Verde on Monday.
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