Elyounoussi, 18, has already had to turn down two chances to train with Premier League Champions Chelsea, and now Portsmouth, currently fourth in the table, has asked to have a closer look at the Fredrikstad striker.
The teenager confirmed to newspaper Fredriksstad Blad that Portsmouth have long been interested in him.
"I got to know that they had been watching me for six months and that they wanted me to train with their first team," Elyounoussi told the newspaper.
But the teenager has decided to put school ahead of football this time.
"I had just said I couldn't attend a session with the national Under-21 team because of schoolwork, so I couldn't turn around and say yes to a tryout," he said.
Elyounoussi made it clear that so far it has just been a question of bad timing rather than reluctance to show what he can do in England. In January he is hoping to make the trip to Portsmouth and fit a trial at Chelsea's Stamford Bridge in as well.
