Speaking exclusively to Football FanCast, former Arsenal striker John Hartson has cast doubt on the future of Tottenham Hotspur midfielder Dele Alli.

The England international was once a mainstay and a key man in Mauricio Pochettino's side, but he just hasn't looked the same player in the previous 18 months or so.

While he was suffering from injury at the beginning of he campaign, the 23-year-old has been limited to just 30 minutes of Premier League action since his return, and was left out of the squad entirely for the 2-1 defeat against Leicester City last month.

Hartson has highlighted the situations of the former MK Dons man, rated at £81m by Transfermarkt, and believes that Mauricio Pochettino could soon have another issue to deal with on top of the likes of Christian Eriksen, Toby Alderweireld and Jan Vertonghen all being out of contract next summer.

He said: "You've gotta look at players like Dele Alli who's not in the team. If he sees three or four players leaving and then all of a sudden his agent is telling him a huge club wants to buy him. All of a sudden there becomes another issue.

"That's where managers earn their crust in situations like this."

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There will undoubtedly be some frustration from both sides of the coin in the current situation, with Alli wanting to be on the pitch making a difference and the club needing the player who was so influential for them in the past - after all, he has 53 goals and 49 assists in 188 games for the north London side.

The Englishman was handed a chance from the start against Bayern Munich on Tuesday to be fair, although it would be difficult to say he grasped it with both hands seeing as the hosts were thrashed 7-2 in north London.

That is the type of result that could lead to key players considering whether their own personal aims can be met in a white shirt, including Alli even if he clearly isn't performing as well as Tottenham know he can.

This could be yet another headache for Pochettino to deal with if Hartson proves to be right about the 23-year-old.