Birmingham City have made their eighth summer signing by bringing in Doncaster Rovers midfielder David Cotterill.
Cardiff-born Cotterill, 26, had been offered a new deal by Doncaster.
But he chose to leave South Yorkshire for Birmingham on a two-year contract to move closer to his family in Wales.
Welsh international Cotterill, who can play on either flank, has won 20 full caps for his country.
He began his career as a professional with Bristol City in 2004, before moving for £2million to Wigan Athletic, where he spent time out on loan with Sheffield United, Portsmouth and Swansea City, who he then joined on a 'permanent' contract in 2010.
Having moved to Barnsley on a short-term deal in February 2012, Cotterill then signed for Doncaster in the summer of 2012, since when he has netted 14 times in 93 appearances.
The last of them was in the 1-0 defeat at Championship winners Leicester City which sent Rovers down on the final day of the Championship season.
Apart from Duffy, Blues have signed Dundee United defender Gavin Gunning and Burnley utility man David Edgar, as well as re-signing former loan striker Wes Thomas from promoted Rotherham United.
Clark has also signed two other defenders, Jonathan Grounds, from Oldham Athletic, and Grant Hall, who has moved on a season's loan from Tottenham Hotspur - plus and MK Dons midfielder Stephen Gleeson.
Meanwhile, City have signed 18-year-old Blues Academy centre-half Nat Kelly on his first professional contract with the club.
Birmingham have also signed two teenage goalkeepers, Connal Trueman and Callum Preston, both 18, on their first professional deals.
All three players have signed a one-year contract, with a further one-year option.