His return came with Schalke in January 2018 and he made five appearances before a switch to Reims in France 12 months later, where he played 11 games. In September 2019, he completed a season-long loan move to newly promoted La Liga side Real Mallorca, where injuries once again restricted him to a handful of appearances.
Having recovered, Baba appeared on occasions for our development squad in the first half of 2020/21 and joined PAOK in Greece during the winter transfer window, where he made 17 appearances and scored one goal.
The 27-year-old joins a Royals side enduring a difficult start to the season, with three defeats from their opening four Championship games. They are next in action away at Huddersfield Town this weekend. His new Chelsea contract runs until the summer of 2024.