Arsenal manager Mikel Arteta admits the club must sign another centre-back this summer.
Speaking after Sunday's win over Watfotd, Arteta confirmed Shkodran Mustafi would miss the start of next season after injuring his ankle.
The German now joins fellow centre-back Calum Chambers and Pablo Mari on the long-term injury list, leaving Arteta needing reinforcements.
"It looks really nasty," said the Spaniard of Mustafi. "He pulled the tendon off the bone in his hamstring and that's normally a lot of weeks."
He added: "I mentioned three central defenders that are not available and we haven't had [two of them] them available for a long time during the season.
"We will have to address that."
