Arsenal will look to buy another centre-back once they complete a deal for William Saliba.
18-year-old Saliba is on the verge of a move to the Gunners, after a 27million deal was agreed with Saint-Etienne.
He will be loaned back to the Ligue 1 club for the 2019/20 season.
Metro says manager Unai Emery now wants to sign a centre-back who can immediate help his leaky defence.
The North London outfit have a much publicised budget of 45m.
Emery is considering selling error-prone centre-back Shkodran Mustafi to fund the deal.
