Sokratis Papastathopoulos has joined Olympiakos on a deal until 2023 after his Arsenal contract was mutually terminated.
The 32-year-old joined the Gunners in July 2018 and was the third major signing of Unai Emery's reign, coming a day after the acquisitions of Stephan Lichtsteiner and Bernd Leno.
The centre back had a good start to life in north London, making 40 appearances in all competitions in his debut season at the club as Arsenal finished fifth and reached the Europa League final.
However, the arrival of Mikel Arteta in December 2019 made the Greece international's position more uncertain as he started just four league games in the rest of the season and saw his regular run in the side during the triumphant FA Cup campaign slowly peter out, coming off the bench on 89 minutes in the 2-1 win in the Final against Chelsea in August.