The Welshman has been on fire for Spurs lately, having scored six goals in their last six matches.
Speaking ahead of Tottenham's last-16 first-leg tie against Dinamo Zagreb in the Europa League on Thursday, Mourinho told reporters: "I want to keep the momentum going but I need to manage him.
"The communication is very good and I think he trusts me. In this moment we are deciding together what to do.
"The other day during the [Crystal Palace] match I found Andre Marriner the fourth official was finding it annoying because we were talking so much.
"I was asking '10 minutes more? 20 minutes?'. He's playing very well.
"The relationship with him is very good I think and of course I would like him to play 90 minutes in every game but he can't."