Sergio Ramos has sustained another calf injury that casts early doubt on the Paris Saint-Germain centre-back being fit to face his former side Real Madrid in the Champions League.
The 35-year-old has been hampered by a series of niggling issues since arriving at PSG from Madrid, where he had spent the previous 16 seasons.
He played a part in PSG's last two matches, but a low-grade muscle problem suffered in training on Thursday could see the defender facing another spell on the sidelines.
PSG confirmed the news on their website on Sunday, with further tests planned for the middle of next week, and Mauricio Pochettino is unsure how long Ramos will miss.
"You never know with an injury. You have to follow the evolution. We don't know the duration of his unavailability," Pochettino said at a news conference.
Ligue 1 leaders PSG are set to host Madrid in the first leg of their Champions League last-16 tie on February 15, before travelling to the Spanish capital three weeks later.
Ramos has played just five times for Pochettino's side in all competitions since arriving in July, totalling 284 minutes of action on the field.
The 15 LaLiga games Ramos started in 2020-21 was the fewest he managed in a campaign for Madrid and a big drop from the 35 games started the season before.
Indeed, he played just eight matches in all competitions at club level in 2021, while his last appearance for Spain was against Kosovo last March.
PSG will also be without forward Neymar and midfielder Georginio Wijnaldum for Monday's Coupe de France last-16 tie with Nice.
Wijnaldum is expected to return from an ankle sprain at the end of next week, while Neymar – who has not played since November – will be further assessed on Monday.
However, Pochettino can still call upon superstars Kylian Mbappe and Lionel Messi for the cup match.
Messi has had a chance to work on his fitness this week, having not been included in Argentina's latest squad after recently being struck down by coronavirus.
And ahead of the Nice match, Pochettino has been encouraged by what he has seen from compatriot Messi.
"We are very happy with what Leo has done in training this week," Pochettino said. "He has trained well. He is in good condition to start.
"For Kylian, it's a question of complicity. Their connection is starting to see each other. They are two very great footballers.
"It's been a good week of work. I'm happy because we were able to work on the tactics, not just the physical side. We hope that this work will be seen by the end of the season."