Gabriel Jesus is set to have a scan as Arsenal seek to learn the full extent of his groin injury.
The striker picked up the injury in training on Thursday and was forced to miss the Gunners’ 2-0 win at Villa Park on Saturday.
Jesus will now undergo a scan and Arsenal face a nervous wait as they seek to discover how long he will be out.
“Unfortunately on Thursday in the training session, just at the end he felt something in his groin,” said Arsenal manager Mikel Arteta.
“We’ll need to assess him. We need to have an MRI scan to see, but he wasn’t available for the game.
“We have to see [how long he will be out]. Probably tomorrow or Monday we’ll have the results to see if it’s a matter of days or weeks. We don’t know.”
It is unclear if Jesus’ injury will impact how Arsenal act in the final days of the transfer window, which closes on Friday.
Fellow striker Eddie Nketiah had been closing in on a move to Nottingham Forest, but he was on the bench for the game at Villa.
Arteta has admitted he would like to bolster the squad and they are set to sign Real Sociedad midfielder Mikel Merino in the coming days.
“We are really happy with the squad,” he said. “It’s true we had an injury with Gabriel Jesus and we missed him. We are a little bit short and if we can do something then we will do it.”
Arsenal maintained their perfect start to the season by beating Aston Villa and they had goalkeeper David Raya to thank.
The Spaniard made a stunning save early in the second-half to keep out Ollie Watkins, when the striker had looked certain to score.
“I thought it was a goal,” said Arteta. “I saw the reaction of the defensive line which was none because the ball goes on the crossbar and we’re all watching the ball and I went: ‘No, please’.
“Then I see the striker in that position and normally it’s a goal. David’s reaction is unbelievable.”
