Zibanejad appeared in nine games for the Senators this season, with one assist and a minus-3 rating. A 10th game with Ottawa would have meant the 18-year-old was sticking in the NHL.
The Stockholm native played his ninth and final game with the Senators on Tuesday night in Carolina.
"I really wanted to stay but they have more experience in this stuff than I do," said Zibanejad, who was taken sixth overall at June's draft. "I think this is best for me and I'm excited to go back home."
Ottawa can't recall him until his European season is over, unless it's under emergency circumstances.
Djurgardens has assured the Senators that Zibanejad will play a crucial role with the team, including first-line minutes and power-play time.
"He might not reach that status with our team this year," said Senators general manager Bryan Murray, adding the decision was a difficult one.
"We think for the long-term development of him, to give him an opportunity to become what we believe he has a chance to become, and that is a quality NHL player, that this is the right step for him at this moment."
The Senators believe Zibanejad has great potential and want to ensure his development progresses.
"I think the reason we're probably sending him back is that we want him to have the puck, we want him to have a chance to score points, to be a legitimate top-six NHL player," Murray said. "I think at 18 years of age, he was playing the last little bit to survive and not make mistakes, rather than be a creative kind of kid that we think he'll turn out to be."
While he would have enjoyed the opportunity to play with the Senators, Zibanejad is looking at the decision as an opportunity for personal growth.
"I guess I get a bigger role back home and I feel comfortable with the game and I feel comfortable with everything outside the ice and just focusing on improving my game and improving all those small details that I have to do to make the team next year," he said. "It's sad, but on the other hand it's a good thing for me and a good option for me to improve my game.
Zibanejad will also be eligible to represent his country at the world junior hockey championship in Alberta this winter.