Argentina have no ready-made replacement for midfielder Giovani Lo Celso who is in danger of missing the World Cup due to a hamstring injury, coach Lionel Scaloni has said.
They are already fretting over injuries to Paulo Dybala and Angel Di Maria but losing Lo Celso, a key player in their Copa America win and World Cup qualification, would be a huge blow.
Lo Celso is a crucial part of Scaloni's midfield formation along with Leandro Paredes and Rodrigo de Paul.
"Numerically there is a replacement, but football-wise there is not," Scaloni told TyC Sports. "There are others with other abilities, but it is evident that he has given us a lot."
The 26-year-old Lo Celso was replaced on Sunday 24 minutes into Villarreal's LaLiga match against Athletic Bilbao and the initial diagnosis showed a muscle rupture injury.
Spanish media reported that Villarreal will provide a final update on Monday, with Scaloni saying there was no point bringing him to Argentina for evaluation.
"He is being treated there, with trained people. I want him to arrive healthy."
Scaloni also highlighted the risks of playing the World Cup in the middle of a season and complained about the number of club matches players were asked to play in October.
"That's what it means to play a World Cup in the middle of a championship with a crazy month of October, with matches every three days," he added. "And then give you the players three days before the start of a World Cup.
"Whoever gets on the plane will be fit to play the first match ... but there are a few variations we have to evaluate according to the positions."
Argentina play a warm-up match against the United Arab Emirates on November 16 before their opening World Cup Group C game against Saudi Arabia on November 22. They also face Mexico and Poland in the group stage.