Arsenal boss Arsene Wenger has revealed that Spanish defender Nacho Monreal could miss the Gunners' next four matches with an "inflamed back".
The 32-year-old was forced off during the first half of the London side's 3-0 Carabao Cup final loss against Manchester City on Sunday, and is now ruled out of Thursday's Premier League clash with Pep Guardiola's side.
Wenger has also ruled the player out of the weekend fixture against Brighton but isn't sure over whether he will be back in time to face AC Milan in Europa League competition - or Watford domestically.
"He is out for the two games this weekend - Thursday and Sunday certainly," the Premier League's longest-serving manager said in his pre-match presser ahead of his team's meet with City.
"He might be out for two more games - Milan and maybe one more [Watford]. He has an inflamed back."
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Monreal has made 30 appearances for the Gunners so far this season, all of them being starts, and his absence should come as a blow to Wenger, who is under loads of pressure to qualify for the Champions League after missing out last year.
Arsenal are 10 points off the top four, with 10 games to be played in the top flight, which makes winning the Europa League potentially their best option as it relates to finding a route back into Europe's elite competition.
"It's not always possible to win games," Wenger added in his presser. "We have to live with the criticism, it's part of the modern game. But we have to focus on the next one and respond together in a united way."