Al-Hilal's Brazilian star Gabriel Martinelli dealt the club's fans a surprise blow during Friday's clash with Al-Qadsiah in the Saudi Roshn League.
The eleventh round of the Roshn League took Al-Hilal to Prince Mohammed bin Fahd Stadium in Dammam.
Martinelli lasted until the 49th minute. He went down without any contact from an Al-Qadsiah player, then asked to come off, and Sultan Mendash replaced him.
Physiotherapist Thamer Al-Shahrani identified the problem as a hamstring injury, posting his assessment on his personal account on "X".
In the best case, Al-Shahrani explained, it is a minor strain that would sideline the former Arsenal man for two to five days. The worst case is a muscle tear, which would rule him out for 10 to 14 days.
His exit came after he had put Al-Hilal in front. In the 21st minute he collected a ground pass from England striker Ollie Watkins and lashed it into the back of the net.
That goal underlined his status as Al-Hilal's top scorer this season. Six goals in six Roshn League appearances, and he has now found the net in each of his last four games in the competition.
Simone Inzaghi's side face a crowded run before the upcoming international break. Al-Fateh and Al-Ettifaq await in the Roshn League, with Qatar's Al-Shamal and the UAE's Shabab Al-Ahli to come in the AFC Champions League Elite.