Arsenal manager Arsene Wenger has suggested club captain Thomas Vermaelen may leave the Gunners.
The 28-year-old, part of the Belgium squad at the 2014 Fifa World Cup, has been linked with Manchester United.
Speaking at a news conference on Friday, Wenger said defender Vermaelen is injured but admitted: "It is a possibility that he goes."
Vermaelen, who joined Arsenal from Ajax in June 2009, made 14 Premier League appearances last season.
Wenger said should Vermaelen leave, the club will find a replacement because the Belgian is "an important player in our squad".
And he added he was not finished in the transfer market, despite making four signings already this summer.
The Frenchman has recruited Southampton defender Calum Chambers - who he described as a "long-term goal", Barcelona forward Alexis Sanchez, Newcastle right-back Mathieu Debuchy and Nice goalkeeper David Ospina.
"I am very happy because I did what I wanted and I am still hoping to do more," he said.
"It is 1 August and the transfer window closes on the 31st. It is a long time. We are a bit ahead of what we usually do because the availability on the market was bigger than before."
Wenger added he would not be signing Porto's Colombian midfielder Juan Quintero, who has been linked with a move to the Gunners.
The Arsenal manager also said that Jack Wilshere is "in the best shape" for three years and believes the 22-year-old England midfielder is "rid of his ankle injuries" ahead of a "very important season".