World Cup winner David Trezeguet has been unveiled as the latest Indian Super League signing, joining FC Pune City.
Stuart Gray is still waiting on the 'green light' to bring in new players as his hands are tied by a takeover delay.
The 26-year-old had been out of contract since the middle of January, having originally joined the club in mid-November.
The former Middlesbrough man played eight times under previous manager Derek McInnes and, after the Scot's departure, new head coach Sean O'Driscoll had to wait a couple of weeks to assess Bates fully due to an illness picked up by the centre-back.
City have also announced that development players Kevin Krans and Luke Dobie have signed new 18-month contracts.
The duo, who joined in the summer, have both have impressed academy coaching staff suitably to earn extended terms at Ashton Gate.