Birmingham City will be looking to enjoy a productive start to the summer transfer window.

Not only do they need to replace loanees, but players will also need to come in to replace the players who are set to leave St Andrew's on the expiration of their contracts.

Keeping John Eustace at the helm could be key for them though, with the 43-year-old enjoying a productive first campaign in the Midlands following his appointment last summer.

He is reportedly on Swansea City's radar - but the fact he was born in Solihull and seems settled at his current club could potentially work in Blues' favour.

Although many of their supporters remain unhappy at BSHL, one positive that can be taken from recent years is the fact they have recruited well and that has probably been key to them retaining their Championship status despite their struggles.

Some of their experienced heads may have played a key part in that - and speaking of experienced players - we take a look at a trio of Birmingham first-teamers who are still playing.

Matt Derbyshire

37-year-old Derbyshire has plied his trade for several teams throughout his career in a number of different countries.

He played for Birmingham during the 2010/11 campaign, joining on loan from Olympiacos and scoring two goals in 15 competitive appearances.

That, plus their relegation, is probably why Blues opted against signing him permanently in the end.

Since going on to play in Cyprus, Australia and India, he has now returned to England and has played for Bradford City since the early stages of this calendar year.

Scoring twice in 13 appearances and also having an assist to his name, he hasn't endured the most spectacular start to life in League Two but he's under contract for next year and looks set to stay put in West Yorkshire for now.

Greg Halford

Halford is another player who has played for quite a few clubs - and has plied his trade in quite a few positions too!

Defence, midfield, attack - the 38-year-old has played just about everywhere and is still going strong.

Joining Birmingham on loan from Rotherham United back in 2015, he appeared just three times for the former and didn't make a huge impact because of that.

Arguably, he is a player that never fully fulfilled his potential and his unsuccessful time at Reading may have contributed to that, but you can't fault how long his career has been.

Not afraid of playing non-league football, he's currently at Hashtag United and played a big part in helping his side secure promotion to the Isthmian League Premier Division this year.

Clayton Donaldson

Donaldson is undoubtedly the player on this list that has made the biggest impact for Blues, recording 33 goals in 117 competitive appearances.

Having spent last season at Gainsborough Trinity, Farsley Celtic moved to sign him last month and will be hoping that he can guide them to a much more comfortable finish in National League North next term.

Narrowly avoiding relegation last term, an addition like Donaldson could a game-changer if he can remain fit and in form.