Argentina midfielder Manuel Lanzini is set to miss out on the World Cup after suffering a ruptured anterior knee ligament injury in training.
The news of the knee injury comes as a major blow in the build-up to the tournament, which gets under way in just under a week.
The West Ham star had worked his way into the Albiceleste's first choice team under Jorge Sampaoli and was set to start against Iceland in his country's opening match in Russia.
But he now faces a long spell on the sidelines following the injury as Argentina's preparations for the tournament go from bad to worse.
Having only just scraped into the tournament in Russia thanks to a Lionel Messi-inspired win over Ecuador in their final qualifying match, the two-time winners have been one of the most talked about nations in the build-up for all the wrong reasons.
Sampaoli's decision to leave Mauro Icardi out of his 23-man squad has raised eyebrows given the Inter man finished as the top goalscorer in Serie A last term.
The former Chile boss has also struggled to fit both Paulo Dybala and Messi into the same team, with the Juventus star regularly left on the bench to accomodate for the five-time Ballon d'Or winner - a decision that had benefitted Lanzini in terms of him becoming a regular starter.
As well as that, the squad found themselves pulled into a diplomatic row after the controversial cancellation of a friendly game against Israel amid political pressure.
That fixture was supposed to be the Albiceleste's final warm-up game ahead of the tournament, meaning they will have gone 17 days without on-field action by the time they meet Iceland on June 16.
Sampaoli will now be forced into a tactical re-think following Lanzini's injury and the Argentina boss will be able to call up a replacement for the stricken winger.
The likes of Diego Perotti, Enzo Perez and Leandro Paredes are believed to be among the likely substitutes, but the former Chile boss could also turn to Lautaro Martinez or Icardi.
Argentina follow their Group D opener with games against Croatia and Nigeria on June 21 and 26 respectively.