Geelong coach Chris Scott has ruled out duo Mitch Duncan and Esava Ratugolea ahead of their season opener against the Adelaide Crows.

Duncan has been battling a calf complaint for most of the pre-season, but Scott maintains that it's only minor.

"He's back into training now after really careful management with a calf strain recurrence," Scott said on SEN Breakfast.

"When you get a recurrence with an experienced player, then it's pretty important to be careful with it, which we have done."

RELATED: Geelong Cats 2021 Season Preview

Ratugolea, who played 12 games for the Cats in 2020, suffered a leg fracture at training, with Scott revealing the athletic tall will miss close to the next month.

"He got a kick at training on his lower leg where he previously had a fracture in his fibula and had it scanned multiple times and nothing came up," he said.

"We were optimistic we could get him back in a week or two, but it's sort of persisted a bit and we scanned it again and that fracture has shown up.

MELBOURNE, AUSTRALIA - MARCH 22: Brodie Grundy of the Magpies and Esava Ratugolea of the Cats compete for the ball during the 2019 AFL round 01 match between the Collingwood Magpies and the Geelong Cats at the Melbourne Cricket Ground on March 22, 2019 in Melbourne, Australia. (Photo by Dylan Burns/AFL Photos)

"Total time looks like being four to six weeks away, but disappointing for sure."

In some good news, the Cats have re-signed promising ruckman Sam De Koning for a further two years, staying put at Kardinia Park until 2023.

The 20-year old was taken with the 19th pick in the 2019 AFL Draft, being the Cats second pick that year following selecting Cooper Stephens at pick 16.

De Koning didn't feature for the Cats in 2020 season, but played in the AAMI series and showed signs that he could feature in a game or two this year.