The Gunners have signed the Greek centre back for a fee said to be worth £17.7m. He has proven to be a dependable defender in Germany and he soon became a first team regular for BVB making 43 appearances in all competitions. It is undoubtedly a solid signing, made better by the timing of his arrival.
In recent years, Arsenal's transfer windows have been largely unsuccessful, due to the fact that they have often left it far too late to get deals across the line.
However, this summer has already seen Arsenal make three signings, all of which being players who have improved positions that required urgent attention. One ex-Arsenal man, Ian Wright, has taken to Twitter to express his joy at the fact that Arsenal are finally getting deals done quickly and efficiently.
Unai Emery has already singed right back Stephan Lichtsteiner and goalkeeper Bernd Leno and has strengthened his back line further with the acquisition of Sokratis.
Wright also noted that the signing is successful due to the fact that Sokratis already has 'friends' at the club in the shape of former Borussia Dortmund players Henrikh Mkhitaryan and Pierre-Emerick Aubameyang.
Time will tell whether Sokratis will be a success at the Emirates, but there is no doubting that Arsenal's transfer business has been uncharacteristically quick and efficient so far this summer. If they continue in the same vein then there is a chance that they can propel themselves back up the Premier League table.