Stoke City have endured a terrible start to the season when you consider they were favourites for promotion before a ball was kicked.

Despite the significant investment that has gone into the team, combined with keeping stars such as Jack Butland and Joe Allen, the Potters have just one win to their name in the league.

They already sit nine points behind leaders Leeds and things need to improve quickly for the Staffordshire side.

With the transfer window shut, Gary Rowett doesn't have many options when it comes to improving the squad, although he can look to free agents.

Whilst Stoke should have a good enough squad on paper, even at this early stage you can see things aren't working. Therefore, a new signing or two could be the lift that people at the club need.

Here we look at six out-of-contract players that could do a job for the Potters...

Defensively Stoke have been a shambles at times this season and Polenta could change that.

The 26-year old centre-back has been capped by Uruguay at youth levels and has been called up to the senior squad and although he didn't play it highlights the ability he has.

Capable of playing left-back as well, he would give Rowett another option.

The one-time England international left Dundee last week after a promising spell in Scotland.

He has had his problems both on and off the field over recent years but seems to be in a better place now and if he rediscovered his old form, Caulker would be a standout performer in the Championship.

The former Hamburg right-back left the German side after they were relegated from the Bundesliga.

Over the years he was a steady performer in the top-flight and would be a coup for Stoke if they could persuade him to drop to the Championship.

Whilst Stoke have several midfield options, few would be like Yacob, who is an aggressive, disciplined defensive midfielder.

With good experience and knowledge of the English game, he would be a good addition for most Championship sides.

If Rowett wants more creativity and flair in the final third then former Wolves winger Sako would be the perfect signing.

He has real power, a superb left-foot and proved in his time in the Black Country that he can be a star in this division.

Another major problem for Stoke has been scoring goals, so Rowett may want another number nine.

Whilst Mbakogu has never been the most clinical, he would be able to hold the ball up and bring others into play. That in turn could make the team much more productive.