The left-back spent last season on loan at PAOK Salonika and the Greek club were interested in keeping him.
But negotiations between PAOK and Chelsea broke down and his agents started looking for a new club this summer.
Rahman featured in pre-season for Chelsea, but is miles away from their first-team plans and Reading are now close to signing him.
An agreement is in place between the two clubs over a loan deal and it has been claimed that he will soon undergo a medical.
Reading are set to put him through the mandatory checks today ahead of him signing a one-year contract with the club.
If the deal goes through, it would be his six loan spell since joining Chelsea from Augsburg in 2015.
He has had loan spells at Schalke, Stade Reims, Mallorca and PAOK ahead of his potential move to Reading.
The Ghanaian has made just 23 senior appearances for Chelsea despite being on their books for six years.
