Cascarino criticised Ndombele's fitness and says he is struggling to adjust to English football.
In the Times, Cascarino said the Frenchman does not look fit enough for the demands of the Premier League yet after observing his last two performances.
He said: "In the 24 games Tanguy Ndombele has played for Tottenham this season, he has come on as a substitute or has been substituted in 19 of them. He reminds me of Tiémoué Bakayoko when he moved to Chelsea. He has lots of athletic ability but he just doesn’t seem to use it.
"He is not a passing player but he also doesn’t seem to have any endurance — Chelsea’s midfield walked all over him and Harry Winks. He came on against RB Leipzig with 25 minutes to go and he was lying on the floor at the end. He has been in England for six months now and I am not sure he is capable of getting up to the Premier League’s pace."
Ndombele is Tottenham's record signing and that brings with it a great deal of pressure and expectation - it's fair to say he isn't living up to it so far.
It can take new signings a fair bit of time to adjust to the Premier League; the contrast between Manchester United Fred between this season and last is huge, for example.
As Cascarino eludes to, having that base level of fitness to deal with the demands of the league is an absolute essential, especially for a midfield player.
At a time when Spurs have been hit by injuries, they need all their other stars to step up to the mark and they may well want to see more from Ndombele.
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