Arsenal are close to signing centre-back Sokratis Papastathopoulos from Borussia Dortmund for a reported £16m.
The 29-year-old Greece international has a year left on his contract with the German Bundesliga side.
It is the latest step in Arsenal's drive to rebuild their defence with experience and leadership.
The Gunners are also working on a deal to sign Switzerland right-back Stephan Lichtsteiner, 34, on a free transfer from Juventus.
The Premier League club intend to bolster their squad with signings who are immediately ready for first-team football and, over time, continue to recruit younger players for the medium to long term.
An example is Papastathopoulos' countryman Konstantinos Mavropanos, 20, who joined in January and was the first signing overseen by new head of recruitment Sven Mislintat, formerly chief scout at Dortmund.
Former Genoa and AC Milan defender Papastathopoulos continues the trend and will help compensate for the loss of captain Laurent Koscienly to an Achilles injury.
The departure of manager Arsene Wenger and arrival of head coach Unai Emery has seen Arsenal adopt a continental model in which Mislintat will lead on recruitment alongside Emery, head of football relations Raul Sanllehi and chief executive Ivan Gazidis.
Emery will contribute to the decision-making process and retain power of veto, while it is understood proposed signings were discussed with head coach candidates during the interview stage.