January transfer window: Birmingham City make £4m bid for former Wolves winger Bakary Sako

Blues boss Gianfranco Zola is ready to make the now Crystal Palace wide man the club's most expensive signing in seven years, according to reports.

The Italian has lost three and drawn one of his four games in charge at St Andrew's following the club's 3-1 home defeat to Brentford.

Zola replaced Gary Rowett last month and has £9million left to spend in January, having already used £1million to turn Lukas Jutkiewicz's loan from Burnley into a permanent switch.

Mali international Sako has played just four times for the Eagles this season and has not started in the Premier League.

He is yet to featured in new boss Sam Allardyce's first two games but was an unused substitute in their 2-0 defeat at Arsenal.

He joined from Wolves on a free transfer in 2015 and scored in his first two appearances but played just 21 more times during an injury-hit first season.

During his time at Wolves, Sako was a fan favourite having made over 100 appearances, scoring 38 goals.

Wolves were linked with a move for the former Molineux star, but the club have talked down any chance of a move.

Sporting director Kevin Thelwell didn't rule a move for Sako, but suggested there was nothing on the cards at the moment.

He told the Express & Star in December: "It's a very difficult one to do. He'll be on a good Premier League salary and he did play a part with when he returned from injury (last month), plus there's the African Cup of Nations.

"There are lots of ifs, buts and maybes."

Should Birmingham complete a move they will be without the 28-year-old for the African Nations Cup in Gabon with Mali opening their campaign in Egypt in two weeks' time.

The club last spent over £4million when they bought Nikola Zigic from Valencia for around £6million in 2010.