The midfielder started his career with Hamilton Academicals before spells with Millwall, Raith Rovers, Hibernian and St Johnstone.

BBC: Bristol City wrap up Hartley deal

Hartley, who started his career with Hamilton and also had spells with Millwall, Raith Rovers, Hibernian and St Johnstone, had been with Celtic since 2007.

BBC: Hartley and Dutchman leave Celtic

Sutton, who began his career with Tottenham before heading for Raith Rovers and Millwall, joined the Buddies from Dundee in 2005.

BBC: SPORT | Football | My Club | St Mirren | Buddies give up on striker Sutton