19-year old left-back Warren will travel to England this week to link up with his new teammates where he will continue to further his development.
Warren admitted it was a great opportunity to experience football in a completely new environment.
"It's an amazing opportunity," said Warren.
"I learned so much just during the two weeks I was there and I can't wait for this experience."
Mariners chairman Peter Turnbull was excited for Warren and also thanked Sheffield for taking a chance.
"It's a fantastic opportunity for Marc and I know he is really excited," said Turnbull.
"The club is excited too because it's just another vindication of the youth policy we have embarked upon this season.
"I'd like to thank (Sheffield United Chairman) Kevin McCabe and (Manager) Micky Adams for not only showing faith in Marc but also recognising the talent of youngsters here at the Mariners and in Australia.
"I'm delighted that our relationship continues to strengthen."