Arsenal forward Alexandre Lacazette will be out of action until next month because of an ankle injury, the north London club said on Friday.
The 28-year-old French forward, who has scored two Premier League goals this season, has been playing through pain for the past few weeks but was advised to rest to ensure he did not aggravate the injury.
"After assessments to an ongoing ankle issue, we have advised that Alex will need to rest and strengthen his ankle to regain full fitness," Arsenal said in a statement.
"Alex has been playing through this injury for several weeks. He is likely to be back in action in October."
Earlier on Friday, Arsenal manager Unai Emery confirmed defenders Kieran Tierney and Hector Bellerin are both close to being available for first team duties after injury.
Bellerin has been on the sidelines for almost nine months following knee ligament damage, while Tierney is waiting to make his Arsenal debut having arrived from Celtic with a groin problem in addition to undergoing a hernia operation.
"They are now close to us but they need to continue to work. They need to take their time to feel comfortable so they can play," Emery told a news conference ahead of Arsenal's Premier League match at Watford on Sunday.
"It depends how they can progress in the next few weeks. Maybe we will decide at the beginning to play them first with the Under-23s to be ready with us.
"Maybe they can take confidence and rhythm and be ready to play for us 100%."
Emery confirmed forward Nicolas Pepe will be involved this weekend despite withdrawing from the Ivory Coast squad due to fitness issues, while defender Rob Holding is nearing full-fitness and could be involved in cup competitions.
"Rob Holding is the same situation but he earned time with matches with the U23s. We need to decide if he will play," Emery added.
"Next week we start with the Europa League and then the Carabao Cup, so with more U23 minutes, he can be ready to give us a performance."