There is a lot of optimism around Birmingham City right now after the brilliant job that Lee Bowyer did to keep the team in the Championship.

The former player inherited a team in a mess and relegation to League One seemed a real possibility, however Blues showed automatic promotion form after Bowyer's appointment to confirm their safety with games to spare.

Now, the challenge for the boss is to build on that and to create a squad that's capable of challenging further up the table.

But, the reality is that Bowyer won't have significant funds to work on the squad, so he may have to be shrewd in trying to identify free agents who can make an impact.

Here we look at NINE players who are out of contract this summer that Blues should be considering...

Bringing in a 30-year-old centre-back may not excite the fans, but Lees is a player who Bowyer could get the best out of.

Since his appointment, Blues have been brilliant defensively and it's down to the manager not complicating things. He wants his centre-backs to be dominant physically and aggressive, which Lees is perfectly capable of.

Whilst he would struggle to get in the XI initially, Blues probably are one short in that department, so this could be a low-cost move to beef up the depth at the back, and the squad would be getting someone who is a real leader and Lees has plenty of Championship experience.

The Sunderland man has been excellent for the Black Cats over the past year, and their failure to win promotion means that there's every chance O'Nien could be on the move.

Capable of playing centre-back, right-back or in midfield, the former Wycombe man is a manager's dream and his work-rate and honesty would make him a favourite to the Blues support. Plus, such versatility is extremely useful over the course of a 46-game season when the fixtures come thick and fast.

The only issue is the rival interest in him, so Birmingham would have to act swiftly and this would be a coup for them.

Firstly, it should be pointed out that Blues aren't exactly desperate for a left-back, with Kristian Pederson and Steve Seddon on the books. But, that doesn't mean that Douglas wouldn't be a smart signing.

As well as having promotion-winning experience at this level, the Scotsman is also brilliant on the ball. Bowyer has put a real focus on set-pieces since coming in, and having Douglas' delivery in the team would make them even more of a threat. Plus, Lukas Jutkiewicz would love playing with someone that has the quality Douglas does in his left foot.

The midfielder had a loan spell with Blues earlier in his career and the fact he only played three games shows that it didn't exactly go to plan.

Nevertheless, Walsh has improved a lot since then and he has the sort of qualities that Birmingham lack in the middle of the park. The former Everton man is brave in possession, looking to break the lines with his passing and he can drive forward as well.

His injury record would be a concern, but Walsh will be desperate to prove himself after a tough spell with Bristol City and that sort of attitude would be welcome by the manager.

The left-footed player is another who would provide Bowyer with options in different positions and he does have quality on the ball.

Reach was a top player for Sheffield Wednesday a few years ago but he has lost his way in the past season or so and the truth is that many Owls fans would have welcomed his departure.

But, at 28-years-old, Reach should still have a lot to offer and Bowyer could be the man to help the player get his career back on track. If Reach could rediscover his best form, he would bring something different to Blues and would be a good addition.

An issue that Bowyer has to address in the window is the lack of pace that the team have. Whilst results were hugely positive since he took over, they have had to grind out the wins.

The challenge now is to evolve and play on the front foot, so adding a direct, quick winger like Harris would make sense. He will be available after leaving Sheffield Wednesday and he would offer Bowyer a good option down either flank. Blues do have plenty of options out wide already, but not many have stood out, so Harris could come in and nail down a regular place in the XI.

There's no denying that this by some way the most ambitious name on the list, but that's not to say it's impossible, even though some bottom half Premier League clubs have been linked with Gauld.

However, the prospect of becoming the main man at St. Andrew's may appeal, and the Scotsman has the ability to be the creative outlet that Blues are lacking.

Capable in possession and a goal threat, Gauld has the potential to be a top player in the Championship and it would be a major coup if Bowyer could convince him to come to the west Midlands.

Another issue that needs to be addressed is the lack of goals, so when a player like Waghorn is available, it's something that Blues should consider.

Admittedly, his form last season wasn't great, but he has hit double figures in two of the past four years, and he could thrive in Bowyer's setup that would allow him to play alongside a target man like Lukas Jutkiewicz or Sam Cosgrove.

Plus, he is another player who would bring Championship experience and wouldn't need time to adapt to the league. So, whilst he may underwhelm some fans, Waghorn could get the goals Blues have been lacking.

Another striker who Blues should consider is Connor Wickham, who is set to leave Crystal Palace.

Firstly, there's no pretending that it wouldn't be a risk, because his injury record over the years is a major worry. Yet, if he does stay fit, Wickham has the ability to make a real impact in the Championship as he can link play, hold the ball up and score goals.

So, on a free transfer it's a move that Blues should consider and once again, the Bowyer factor could be key as he would back himself to get Wickham fit and firing.