Melbourne, Jan 24 : Australia have suffered a serious blow before the crucial one-day clash against South Africa on Monday with main pacer Nathan Bracken being ruled out due to a calf strain.

Bracken's form has been one of the few highlights for the home side with the tourists leading the five-match series 2-1 ahead of game four at Adelaide Oval.

The South Africans have struggled to come to grips with Bracken's variety of deliveries with Proteas skipper Johan Botha saying on Friday night that Bracken was always "one step ahead of us."

Bracken will be replaced by Queensland paceman Ryan Harris, FOX Sports reported.

Australian team physiotherapist Alex Kountouris said scans had shown that Bracken had sustained a minor strain from Friday night's clash at the SCG, which South Africa won by three wickets.

"We will continue to assess the injury over the next few days before a decision can be made on Nathan's availability for the Perth games against South Africa and New Zealand," Kountouris said.

Bracken is currently second on the International Cricket Council's one-day bowler rankings and national chairman of selectors Andrew Hilditch said he would be missed in Adelaide.

"It is disappointing to lose Nathan Bracken for such a critical game, particularly given his current form and world ranking in the one-day format of the game," he said. (ANI)