The Mali international was due at Ashton Gate on Thursday afternoon to discuss terms with the Robins and have a medical.
The fee is believed to be around £500,000. Reading paid the Portuguese side Boavista £1million for him in May 2007.
Defender Michael Hart has joined the Scottish Premier League side Hibernian after having his contract cancelled by Preston North End.
Middlesbrough have held talks with Glasgow Rangers over a move for their Scotland international midfielder Kevin Thomson.