Striker Oli Hawkins has joined League Two Mansfield Town on a two-year deal for an undisclosed fee.
Hawkins, 29, moved to the Blues last summer after leaving Portsmouth and made 10 starts and 13 sub appearances, scoring once.
"Oli will add a real presence in both penalty areas, something which we missed last season, both defensively and offensively,” Stags boss Nigel Clough told his club's official website.
"He’s an unselfish player and his assists ratio is very good, but his presence in both penalty areas is the main reason why we’re signing him.
"He’s been playing in teams who have competed towards the top end of League One in the last few seasons and we’re excited to add him to our existing line-up of strikers.”
The frontman was among the players told he could find a new club by manager Paul Cook at the end of the season.
Elsewhere, ex-Blues winger Danny Rowe has signed a new one-year deal at Burton Albion having joined the Brewers on a short-term contract in February after leaving the Blues at the end of 2019/20.