Mikel Arteta confirmed William Saliba came off with an injury after Arsenal tightened their grip on top spot with a 1-0 win over Crystal Palace.
Having missed the first half of September with an ankle problem, Saliba returned to the fold to play a part in the Gunners’ last seven matches in all competitions.
But the centre-back managed just 45 minutes of today’s London derby, with Cristhian Mosquera taking up his place alongside Gabriel Magalhaes after Eberechi Eze’s stunner against his former side.
Arteta has taken a cautious approach with Saliba’s minutes in recent weeks and opted to start Mosquera in Arsenal’s dramatic 2-1 victory over Newcastle last month.
The 24-year-old Frenchman – who has been named in the PFA Team of the Year for the last three seasons – was only deemed fit enough for the substitutes bench on that occasion at St James’ Park.
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The Arsenal head coach faces an anxious wait to learn the severity of Saliba’s latest setback ahead of a busy and crucial period for the club.
The Premier League leaders play host to Brighton in the fourth round of the Carabao Cup on Wednesday night before returning to top-flight action in a week’s time away to Burnley.
‘The first one (injury) was Willy, he had to be out after the first half,’ Arteta replied when asked for an update on Saliba at his post-match press conference.
‘I don’t know (the exact nature of the injury), not because I don’t want to tell you! But because I don’t really know.
‘On Willy, there are two things related to his substitution.’
Declan Rice and Riccardo Calafiori were also substituted in the second period, both appearing in some discomfort as they left the field at the Emirates.
‘Declan was also struggling from the first half with a knock that he took,’ Arteta explained.
‘And Ricci (Calafiori) as well, so let’s see how they recover.’
On Rice’s issue, Arteta added: ‘With Declan I don’t really know because it was knock, whether it was a calf or an achilles.’
There was also some concern surrounding Gabriel Martinelli’s fitness, who was speaking with Arsenal’s medical staff in the tunnel shortly after the final whistle.
But Arteta is confident the Brazilian did not pick up a serious injury, telling reporters: ‘Yeah, I think so (Martinelli is OK)
‘We have to check that out. He was a bit uncomfortable and he said he felt something.
‘We don’t know whether it’s a muscular issue or not so tomorrow we will have more news.’
Arteta was delighted with Arsenal’s resolute performance against Palace team he deems ‘one of the best in terms of organisation’ in the Premier League.
‘I just told the boys that they will probably value this victory more than any other victory this season because we knew the difficulty of it,’ the Spaniard explained.
‘We come after playing every three days. You have a big opportunity as well, with the things that happened during this weekend.
‘I knew we were playing against a team that has been one of the best recently in terms of organisation, how difficult they make it, how frustrated they can make you.
‘The moment you lose that concentration, they will punish you for sure.
‘We’ve managed to be more stable, playing the game we have to play. We found a way to score in the first half and in the second half we attacked better and we were more fluent.
‘But at 1-0, we knew we had to suffer. To keep a clean sheet again was very important.’
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