Arsenal have expressed interest in signing Germany international Matthias Ginter from Bundesliga side Borussia Monchengladbach.
Unai Emery wants to bring at least three new players to Emirates Stadium at the end of the season, with defensive reinforcements his priority.
The north London giants have shipped 36 goals in 25 Premier League fixtures this season, the most of any team in the top six.
Shkodran Mustafi has failed to prove his £35 million transfer fee after arriving from Valencia in 2016, while other defenders have struggled with injuries.
Shkodran Mustafi is also understood to have been placed on the transfer list and the Gunners are ready to sell the unwanted German defender who has failed to prove his worth since the of former manager Arsene Wenger.
The Gunners will attempt to sign a new centre-back this summer, and Sky Sports say scouts are keeping close tabs on Matthias Ginter ahead of a possible move.
It is true that defensively, Arsenal have not been good enough past years. So it was not a surprise to see the trying to sign defenders in January transfer window. But the problems they have will not be solved by signing a player or two.
Clearly, the backline is a problem. The better teams are getting through them far too easily, and it is hard to believe that when Unai Emery says that he is happy with his current defensive options and does not need new players in these positions, the Spaniard does not want to criticise his players publicly.