Wales international David Cotterill made the switch to Blues ahead of the 2014/15 campaign.
The former Doncaster Rovers midfielder joined the club on a two-year deal.
Cardiff-born Cotterill, who can play on either flank, began his career as a professional with Bristol City in 2004, before moving on to Wigan Athletic in 2006 in a deal worth £2 million.
In his time at the Latics he spent periods out on loan with Sheffield United, Swansea City and Portsmouth prior to joining the Swans on a permanent contract in 2010.
Having joined Barnsley on a short-term deal in February 2012, Cotterill was then snapped up by Doncaster in the summer of 2012 and in his first season with Rovers he scored ten goals in 49 appearances, as well as providing the most assists in the division which earned him a place in the PFA Team of the Year for League One.
Cotterill made his Blues debut on 12 August 2014 in the first-round capital One Cup win against Cambridge United.