Arsenal manager Mikel Arteta is sweating over the condition of Gabriel Magalhaes for Saturday's Premier League London derby against West Ham United away from home.
The Brazilian centre-back was one of five scorers in Tuesday's 5-1 Champions League drubbing of Sporting Lisbon, but he was forced off with an unspecified injury in the dying embers.
Arteta was none the wiser about the seriousness of his problem after the match, but as Manchester United are visiting the Emirates in midweek, the Gunners boss should take no risks with one of his key cogs.
Ben White and Takehiro Tomiyasu's knee injuries limit Arteta's options for change at the back, although he still has Jakub Kiwior, Oleksandr Zinchenko and Kieran Tierney - finally back from his Euros hamstring injury - ready and waiting.
The visiting boss could start Zinchenko and move Riccardo Calafiori to a central role, but given the Italian's effectiveness at left-back, Kiwior in for Gabriel seems to be the most likely course of action.
A handful of alterations further up the field may also be in store, as Mikel Merino could offer Thomas Partey a rest to join Declan Rice and Martin Odegaard in what will likely be Arsenal's first-choice midfield from 2025 onwards.
Leandro Trossard continues to thrive as an impact substitute - as his goal off the bench against Sporting proved - but the Belgian is now a candidate to start in place of Gabriel Martinelli alongside Bukayo Saka and Kai Havertz.
Arsenal possible starting lineup:
Raya; Timber, Saliba, Kiwior, Calafiori; Odegaard, Rice, Merino; Saka, Havertz, Trossard
> Click here to see how West Ham could line up for this derby
Ben Knapton
