Arsenal are reportedly closing in on signing defender Sokratis Papastathopoulos from German club Borussia Dortmund after increasing their bid to £15.8m.

According to the Express, the Gunners have stepped up their efforts to land the defender with a fresh bid after their initial approach was rejected by the Bundesliga club. It is claimed that Arsenal had a bid of £10.9m outrightly dismissed by the Germans.

Dortmund are said to be demanding a fee closer to their £20m valuation, but Arsenal feel that the new bid will be sufficient to tempt the club to part with their player.

Arsene Wenger has been on the market for a defender to replace the departed Thomas Vermaelen, and has been linked with a few names through the month. Another Greek defender Kostas Manolas was linked with a move to Arsenal, but he eventually moved to Serie A club AS Roma.

The report also claims that the Greek international is keen on a move to the Emirates, as he is aware that first team chances will be rare to come by with Mats Hummels and Neven Subotic ahead of him in the pecking order.

The 26-year-old defender, who moved to Dortmund from Werder Bremen last summer, has the ability to play in multiple roles. Even though he is primarily a centre-back, he can also play as a right-back and in the defensive midfield position.

Wenger has always been a fan of versatile players and this attribute will make him a good fit for the north London club.

Meanwhile, Gunners defender Per Mertasacker has been singing praises of 19-year-old defender Calum Chambers, who moved to Arsenal from Southampton this summer.

"He has everything. He can play different roles and he will be very important. He comes in and it's easy for him to feel comfortable. He's so composed and he will play a big role," Mertesacker said, as quoted on Arsenal's official site.

"As a person I like him very much because he's calm, he tries to learn and he listens all the time and that is something that is really rare," the German international added.