Ryan Rickelton and Mitchell Starc [Source: @ProteasMenCSA, @cricketcomau/x]Australian captain Mitchell Marsh won the toss and opted to field first against South Africa in the second ODI of their three-match series. At the toss, the seasoned all-rounder confirmed a couple of changes in the Australian playing XI.With Mitchell Starc being the biggest of Australia’s two exclusions, South Africa skipper Temba Bavuma also announced that Ryan Rickelton will not be available for selection for the all-important match.Here, we take a look at the exact reasons behind Starc and Rickelton’s unavailability from the SA vs AUS 2nd ODI on September 27 at the Wanderers Stadium in Johannesburg.Why is Mitchell Starc not playing SA vs AUS 2nd ODIAustralia captain Mitchell Marsh confirmed that legendary fast bowler Mitchell Starc is not playing the all-important second ODI match against South Africa. The interim skipper claimed that Starc has been rested from the Australian playing XI as part of his workload management.Marsh explained that the Australian team management wants to preserve Starc for the time being, especially considering the senior paceman will have a huge role in play in Australia’s upcoming Test series against the Proteas.Also Read- Mitchell Starc Claims Number 1 Spot In ICC Rankings, Dethrones Jasprit BumrahAt the toss, Mitchell Marsh said “Mitchell Starc’s out for Xavier Bartlett. He (Mitch Starc) is obviously building towards the Test match series, and yeah, just build back him up, give him today off.”Why is Ryan Rickelton not playing SA vs AUS 2nd ODISouth Africa is also taking field at the Wanderers Stadium for the second ODI against Australia without one of its key members. At the toss, captain Temba Bavuma confirmed that prolific wicketkeeper-batter Ryan Rickelton will not be playing the game, and the cricketer has been replaced by comeback man and experienced campaigner Aiden Markram instead.Bavuma explained that Rickelton is unavailable for the match owing to “personal reasons”, and will likely return to the Proteas playing XI for the third ODI of the series this week.Notably, Ryan Rickelton is one of the four changes made by the South Africa team management for the SA vs AUS 2nd ODI today in Johannesburg. Apart from Rickelton, players like Tony de Zorzi, Corbin Bosch and Gerald Coetzee are also unavailable and they are replaced by Tristan Stubbs, Duan Jansen and Lizaad Williams in the playing XI respectively. Josh Hazlewood to helm Australia pace attack in Starc, Cummins absenceWith Pat Cummins and Mitchell Starc both not playing for Australia in the second ODI against South Africa, Josh Hazlewood is helming the Australian pace attack.The speedster shared the new ball with comeback man Xavier Bartlett, and even picked up the big wicket of South Africa opener Aiden Markram in the very first ball of the match for a duck. Also Read- Who Has Naman Dhir Replaced In India Playing XI vs West Indies? 1st ODI Toss Report