Arsenal have confirmed that Gabriel Martinelli will miss the first half of the 2020-21 season.
Martinelli damaged the cartilage in his left knee during a training session on June 21, and underwent surgery on the issue later in the month.
The 19-year-old was ruled out of action for the remainder of the current season, which had been an impressive one for the man snapped up for a modest fee of £8 million from Ituano last summer.
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The Brazilian has hit 10 goals in his first 26 appearances in all competitions for the Gunners, despite the fact he has operated in a back-up role behind first-choice strikers Pierre-Emerick Aubameyang and Alexandre Lacazette.
Unfortunately, Mikel Arteta will also be without Martinelli for the start of his first full campaign in charge at Emirates Stadium, with Arsenal releasing an official update on his rehabilitation programme on Thursday.
A statement on the club's official website reads: "Surgery was successful, with consultants and our medical team very encouraged with Gabi’s current progress at this stage of his recovery.
"[He is] currently at our training centre every day receiving specialist attention and support from our medical team. [He] will continue his recovery throughout the close season, with the aim of a return to full training by the end of 2020."
Arsenal have also informed their supporters that Pablo Mari is on course to return to action in September, having been sidelined since the club's 3-0 defeat to Manchester City on June 17.
The 26-year-old had to be withdrawn from the game early in the first half after sustaining ankle ligament damage, and was subsequently sent to Spain to undergo therapy on the injury.
The Gunners' statement added on Mari's recovery: "[Mari] Will return to the UK later in July to resume his rehabilitation at our training centre throughout the close season, with the aim of returning to full training in September."
Arteta has had to maximise the output of his squad in the absence of Martinelli and Mari as Arsenal continue to fight for Europa League qualification.
The Gunners picked up a morale-boosting 2-1 victory over newly-crowned Premier League champions Liverpool on Wednesday, which saw them move to within three points of sixth-placed Wolves in the table.
Next up for the north London outfit is an FA Cup semi-final showdown against City on Saturday, with a crucial trip to Aston Villa set to follow three days later.