Ibrahimovic, 36, enjoyed a spectacular debut season at Old Trafford, scoring 28 goals in 46 games before a serious knee injury curtailed his career at the Theatre of Dreams.
Despite overcoming the career-threatening blow, the Sweden international has been a bit-part player under Mourinho this campaign, with only seven appearances to his name.
But the former Juventus striker says his absence has been down to his refusal to participate in first-team fixtures if he feels he's not going to live up to his high standards.
"I want to get to the point where I can perform as I haven't been able to take part so much during the season," the veteran forward told Reuters. "When I'm ready to perform. It's all about that."