By Editor Wayne Veysey | Former Evening Standard, Press Association and Goal chief correspondent with 17 years experience of breaking big stories, including exclusives like this

Follow me on Twitter @footyinsider247

Sadio Mane has rejected a new contract offer by Southampton to throw his future into doubt ahead of the January window, Football Insider sources understand.

The Saints striker has been offered a five-and-a-half-year deal by the south coast club to replace his existing agreement, which expires in 2018.

But Mane will not sign and this has alerted the 23-year-old’s admirers from the Premier League, who include Manchester United and Chelsea, and will ignite a January scramble for his services.

Mane has scored six goals for Southampton this season, as well as supplying six assists, in all competitions and has maintained the fine form of his debut campaign.

The Senegal international is regarded as the Saints’ prize asset and the club are privately adamant he will only be sold when they are ready to do so.

Manchester United are targeting a new wide player in the January window, Football Insider sources understand.

Louis van Gaal has made it clear to United that one of his priorities is to recruit a mobile wide forward capable of getting in behind defences and creating and scoring goals.

United enquired about Mane last summer but Southampton refused to do business at less than £30million, while the Senegalese has also caught the eye of Chelsea.

Slow coach: Juan Mata does not have burning pace

Slow coach: Juan Mata does not have burning pace

The Saints do not want to sell Mane in January but could face a fight to keep him next summer when he will be in the final two years of his contract.

Van Gaal has been open about United’s need to have more pace in the wide areas.

“You have seen that now we play with Jesse Lingard, and he is not the most speedy winger in the world,” said the Dutchman earlier this month. “Mata is also not the most speedy winger in the world.

“So first we must address that problem and then we can see how we have to play and how we are in balance with playing with speedy wingers.”