Chelsea are preparing a bid for 18-year-old Saint-Etienne centre-back Kurt Zouma. The Mail Online believes the France U20 international could be available for as little as £10m and the Blues believe him to be a cheaper alternative to FC Porto's Eliaquim Mangala.

However, the west London side will face competition for the young Frenchman's signature, with Premier League champions Manchester United reportedly keen on his services as well.

Kurt Zouma (L)

New Chelsea boss José Mourinho has four senior options in central defensive positions, with John Terry, Gary Cahill, Branislav Ivanovic and David Luiz in the squad. However, of these four, Terry is 32 years old and Brazilian international Luiz has been linked with both Barcelona and Real Madrid.

Recruiting a new centre-back is believed to be on or near the top of Mourinho's to-do list this summer and 22-year-old Mangala, a Frenchman of Congolese descent, was believed to be his first choice. However, the Portuguese champions have put a £30m price tag on his services; and given he is contracted to the club until 2016, that valuation is unlikely to drop anytime soon.

Zouma therefore is fast emerging as the target of choice. The youngster said earlier this month, "It is true there [is] interest from various clubs but St Etienne are in the driving seat."

According to ESPN, the player's agent, David Venditelli, Liverpool, United and Juventus were also interested at one point. Their report, however, quotes £8.5m as an acceptable price for the Ligue 1 club.

Zouma has also admitted to a desire to play in the Champions League, telling French newspaper L'Equipe: "The Champions League, it's a mad dream. I said to myself that I was going to stay another year. Having said that, you don't know what might happen this summer. Those are the unpredictable things in football, but it's enriching."

Zouma made 18 starts in the French top division last season, scoring twice and leading his side to fifth and the Europa League for the 2013/14 season.