Southampton manager Ronald Koeman has made it clear to Manchester United that forward Sadio Mane is not for sale after the Red Devils reportedly made an enquiry regarding the availability of the Senegalese striker, according to BBC Sport.

Louis van Gaal has supposedly identified the Saints star as an able alternative for Pedro Rodriguez, who snubbed United for a move to Chelsea, and was unveiled on Thursday 20 August.

The Dutch manager is keen to strengthen his forward line this summer following the departures of Radamel Falcao, Robin van Persie, Angel di Maria and Nani, and has indicated that he is looking for a player with speed and creativity.

However, their initial bid for the Senegalese international has been dismissed by the St Mary's outfit, with Koeman making it clear that none of his players are for sale.

The Dutchman [Koeman] has also admitted that clubs have to deal with rumours regarding their players due to the transfer window spilling into the Premier League season, and believes that such speculation will lead to the player losing focus on his primary objective, which is performing at the highest level on the pitch.

The Saints boss has also hinted that the transfer window should close before the start of the season, as it is mainly the smaller clubs who suffer as the players of bigger clubs are not often subject to transfer speculation.

"We have to deal about rumours from the press and maybe from Manchester," Koeman said, as quoted by The Guardian.

"I don't know – because there is no contact and no bid for nobody and we don't sell any more players. That is very clear in my opinion. We have to deal with the situation. I don't like it because maybe players are thinking and they are not then focused on what they have to do," the former Feyenoord manager explained.

"The timing is always bad. Maybe it's worse one day before we play at home but it's always bad. We keep going. It is not 1 September yet. There are still 10 or 11 days to go, so we will see what happens."

"It is the worst situation for the smaller clubs because nobody talks about the best players of City, United or Chelsea, because they are in the best place to be. But teams like Southampton – they have to deal with this and that is not easy," he added.

"It makes rumours and everyone is talking about it. We have to play and that is difficult. If they don't change the window from 1 September, we will always have these rumours."

However, this has not put off the 20-times English champions, who according to the Mirror are preparing a second bid for the Senegalese forward said to be around the £20m ($31.3m)-mark, after failing with a reported £15m ($23.5m) bid the first time around.

The report claims that the Saints are holding out for a fee closer to £25m, but the Red Devils are hoping that an offer close to their valuation will be enough to land Mane, who is said to have impressed Van Gaal with his combination of speed and goal scoring ability.