The Ghana left-back arrived at Stamford Bridge in the summer of 2015 after the Blues splashed in excess of £20million on his signature from German side Augsburg.
Rahman impressed in the Bundesliga and even ended his 2014/15 campaign having made more tackles than any other defender in the competition that year.
Nevertheless, his move to Chelsea backfired, with the player making a mere 15 Premier League appearances, and spending the majority of his time away on loan.
Since 2016, Rahman has been at Schalke 04, Reims, Mallorca and even Greek side PAOK.
This week, the Chelsea man has agreed his seventh loan move, with the player returning to Reading after spending the last campaign at the Select Car Leasing Stadium where he made 29 starts as the Royals narrowly avoided relegation.
Manager Paul Ince told the club website: "A natural left-back with experience at the very highest level has been a clear priority in our recruitment plans this summer."
Rahman rejoins Reading as they currently sit fifth in the English second tier, looking to build on a strong start to their 2022/23 campaign.
Head of football operations Mark Bowen added: "Since the day his loan spell ended in the summer, we have been hoping to bring him back and I am very pleased we have been able to secure his services for the 2022/23 campaign."