Arsenal striker Alexandre Lacazette has been ruled out until October with an ankle injury.
The club revealed the news on their website and confirmed the France international had been playing with the problem for the last few weeks but now needs to "rest and strengthen his ankle to regain full fitness."
Live Renault Super Sunday
The full statement on Arsenal's website said: "After assessments to an ongoing ankle issue, we have advised that Alex will need to rest and strengthen his ankle to regain full fitness.
"Alex has been playing through this injury for several weeks. He is likely to be back in action in October."
Lacazette has already scored two goals in three matches this season, including the Gunners' first goal as they came from two-down to draw 2-2 at home to Tottenham in the north London derby before the international break.
The 28-year-old will miss Sunday's trip to Watford - live on Sky Sports - as well as their away game with Eintracht Frankfurt in the Europa League on Thursday.
He is also expected to miss the Premier League games against Aston Villa and Manchester United, plus the visit of Nottingham Forest to the Emirates in the Carabao Cup.
Arsenal head coach Unai Emery did have some positive injury news ahead of their game with Watford, however, as he confirmed defenders Hector Bellerin and Kieran Tierney are close to a return to action after injury.
While neither will be available for the trip to Vicarage Road, Emery says they will get minutes with the U23s to regain match fitness.
"They are now close to us but they need to continue to work," the Gunners boss said. "This week they trained normally with us for the first time.
"Next week we want to see them train normally and after we can decide if they can play with the U23s or with us."