Xherdan Shaqiri was forced to withdraw from the Switzerland squad due to an “inflammation of the pubic area”.
Switzerland begin their 2020 European Championship qualifying campaign in Georgia on Saturday, and then host Denmark three days later.
But it emerged on Sunday that Liverpool forward Shaqiri, a key player for manager Vladimir Petkovic, will play no part in those encounters after withdrawing from the squad.
It was unclear at the time what forced Shaqiri to pull out of the squad, but a Swiss Football Association statement soon cleared the situation up.
It read: “The Swiss team must give up the services of Xherdan Shaqiri in Georgia and against Denmark.
“The player suffers from inflammation in the pubic area.”
The injury will no doubt be a worry for Reds boss Jurgen Klopp, who is preparing his side for a crucial run-in.
The Anfield club are competing for domestic and European glory, and the German coach will want a full squad to choose from.
Shaqiri was an unused substitute in Liverpool’s nervy 2-1 win at Fulham on Sunday, a result that moved them back above Manchester City who have played one game fewer.
Klopp’s league leaders are also in the Champions League quarter-finals, where they face a two-legged encounter with Portuguese giants Porto.
Shaqiri has six goals and three assists in 26 games for Liverpool this term, but hasn’t played since the 0-0 draw with Manchester United at the end of February.