Sokratis Papastathopoulos is close to completing his move to Arsenal. (Getty Images)

Arsenal are on the verge of completing a deal to sign Borussia Dortmund defender Sokratis Papastathopoulos, according to reports in Germany.

The Greece international is set to become the first signing of Unai Emery’s reign, although it has been Arsenal’s head of recruitment Sven Mislintat who has played a key role in recruiting the 29-year-old.

Sky Germany report that Sokratis arrived in London on Sunday evening and had a medical on Monday.

Arsenal are due to pay €20 million (£17.5m) for the central defender, who would’ve been out of contract with Dortmund next summer.

Sokratis has been a regular fixture at the heart of Dortmund’s defence for the past four years, while he also has 79 caps for Greece’s national team.

Sokratis had a medical in London ahead of his switch to Arsenal. (Getty Images)

Arsenal are looking to bolster their defensive options even further ahead of the new season and are also targeting Juventus right-back Stephan Lichtsteiner.

Stuttgart centre-back Benjamin Pavard is another player on Arsenal’s shortlist, although the German club have denied any formal approach from the Gunners.

Marouane Fellaini is on Arsenal’s radar. (AFP/Getty Images)

On Monday, reports also claimed that Arsenal have entered the race to sign Marouane Fellaini.

The Belgian midfielder is out of contract with Manchester United this summer, meaning that he would join on a free transfer.