The arrival of Liam Rosenior was expected to revitalise Santos at Chelsea, especially since the pair previously thrived together at Strasbourg. Initially, Santos enjoyed a run of consecutive starts under Rosenior. However, the relationship soured during a match against Burnley in February. Rosenior heavily criticised a player for failing to mark Zian Flemming, who scored a stoppage-time header to snatch a 1-1 draw.
Shortly after, Santos was seen marking Flemming at another corner, hinting he was the culprit. As the season progressed, Rosenior benched Santos, leaving him as an unused substitute in his final two games. An interim spell under Calum McFarlane also saw Santos make a costly marking error against Manchester City.