The 21-year-old scored 17 goals in 65 appearances over two seasons in Portugal and is now focused on continuing his development in Denmark.
”I see it as a good opportunity for me to move to FC Midtjylland. I really enjoyed my time here when I played in the academy. It was like my springboard and the start of my career,” Iheanacho stated.
“I managed to make my first-team debut, which I am incredibly happy about, but at the time the good decision for me was to move to Mafra.
“I got a lot of playing time, and had a really good season most recently. Now I feel that the next step for me is to move back to FC Midtjylland and hopefully get playing time here and continue my development.
“I already know many of the team, as several of those I played with in the U19 team and in Mafra are now playing in the first team. I look forward to being part of the club again, hopefully winning titles and playing in the Europa League.”