Tottenham Hotspur boss did not want to go into detail.
Tottenham Hotspur boss Mauricio Pochettino has indicated Mousa Dembele's recent absence from the team is a delicate situation.
Dembele was left out of last weekend's fixture against Swansea City and did not feature against Barnsley in midweek.
Pochettino says he is being deliberately careful in when he selects the Belgian, but was also cautious with his choice of words and was reluctant to go into detail about the reason.
Pochettino told The Guardian: "I think after I’m here at the club for three seasons, you trust in what I say and our fans trust in our decisions.
“It’s a private matter, a medical matter, and it’s so difficult to speak about – first of all, because I don’t have the vocabulary in English to explain everything properly and then, to make a mistake, is so easy. It’s better to be cautious about what I say.”
Dembele has been suffering with a foot injury and underwent surgery at the end of last season to try and resolve it, but it remains an issue.
The Argentine boss praised the midfielder, referring to him as a 'genius'.
He said: "It is so important to manage him properly. We have very good communication with the doctor, physio, sports science and coaching staff to try to help him because to help him is to help the team.
“He is a player who I have told you many times is, for me, one of the geniuses that I have met in football."
Dembele has been a key part of Pochettino's Tottenham team over the past three years but he is now 30 and appears at present not to be able to play twice a week each week.
Spurs fortunately have multiple options available in midfield but Dembele would be a certain starter if fully fit, and it is no coincidence the match he did play recently was their most important one, a 3-1 win against Borussia Dortmund.