According to journalist Fabrizio Romano, the 35-year-old is set to sign a contract that will keep him at the La Liga club until June 2024.
He will undergo his medical tests on Thursday.
The experienced centre-back has been without a club since his deal with Olympiacos expired this summer.
He was reportedly keen to join Bayern Munich and was hopeful about getting a call from them, per Sky Sports in Germany.
But the Bavarians didn’t contact the Greek footballer and he is now on the brink of joining Betis.
Sokratis previously played for Arsenal. He was brought in by then-manager Unai Emery in 2018 after being impressed with his performances for Borussia Dortmund.
He was a regular starter under Emery, making 40 appearances in his debut season across all competitions.
But his game time suffered following Emery’s departure in November 2019.
Sokratis scored six goals in 69 senior appearances during his time at Arsenal.
He joined Olympiacos in January 2021, helping the club to two Super League Greece titles.
Sokratis mainly plays in central defence but he has occasionally been used at left-back.
His experience could be very useful for Betis, who have made a mixed start to the 2023-24 season.
With three wins from 10 matches, Manuel Pellegrini’s side are ninth in the La Liga standings.
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