Twenty-nine year old Devlin's arrival is initially on loan but he could re-join the club in a full-time deal should he impress.
Blues general manager John Benson told the club's official website: "Devs is due to start training with us tomorrow, with Furlong joining up with them.
"It could lead to a permanent move, but at the moment it's just a loan.
"We've got plenty of strikers at the club, but we haven't got many wide players.
"Devs is a lively player and we need to change things around a little bit and hopefully he'll provide the ammunition for the strikers."