McGain, 37, is yet to play a Test but MacGill believes the Victorian's advanced years would ensure a successful debut.
Kingsmead, the venue for the third Test, starting on Thursday,Mar 18 offers the most spin-friendly conditions in South Africa.
"I am a massive fan of bowlers and cricketers who know their own game," MacGill told the Herald last night.
Meanwhile, Adam Voges has conceded that he might never again be selected for his country after choosing to attend his wedding rather than play for Australia in their limited-overs tour of South Africa.
Voges, who was picked in the 16-man touring party, made plans with his fiancee Kristy more than a year ago to get married in Perth on April 5.