The pair, who were contracted until the end of 2013, will be at Fremantle until to the end of 2015 after agreeing to two-year extensions.
Crozier, 19, was taken with the 20th pick in the 2011 NAB AFL Draft, while Sutcliffe, 20, was selected with pick 71 in the same draft.
"We're really pleased they've committed to the club longer term," Fremantle coach Ross Lyon said.
"As senior coach I'm always pleased to lock away the talent, and those two players were significant on Saturday night."
Crozier, in just his fifth AFL appearance, kicked two goals in Saturday's win against Gold Coast, as he did against the Western Bulldogs in round two, his only other senior appearance this season.
Sutcliffe came on as the sub at Metricon Stadium and had an immediate impact.
It was the sixth time in nine senior matches he has been the sub and Fremantle have won all six.
"It's a sign of confidence by those young players in the club in the direction the development academy, in particular Simon Lloyd (senior development coach), has taken with them in helping them grow," Lyon said.
Fremantle general manager of player management Brad Lloyd said securing the futures of the club’s best young talent was a priority.
"Hayden and Cam are hard-working and dedicated young men and we’re very excited to have them commit to the club," he said.
"We look forward to seeing them continue to develop and contribute in 2013 and beyond."