Shaun Marsh found a place in Australia's Test squad for the upcoming tour of South Africa having made just 275 first-class runs at 34.37 this summer. He has scored one century.

That hundred, an unbeaten 127 against Victoria at the WACA, was Marsh's first in long-form cricket since being dropped from the team after the 2011-12 series against India. In those matches, Marsh made 17 runs in six innings at an average of 2.83.

Last summer, just after Justin Langer had replaced Mickey Arthur's successor, Lachlan Stevens, as the coach of Western Australia, Marsh made 154 first-class runs at 19, with a highest score of 84. He was out of the WA team for much of the season.

Apart from those players in the Test team this summer, 11 other Australian batsmen have made more first-class runs in 2013-14 than Marsh has compiled in the past two seasons combined. In ascending order, they are Adam Voges, Rob Quiney, Ben Dunk, Travis Head, Ed Cowan, Tom Cooper, Phillip Hughes, Cameron White, Ryan Carters, Chris Lynn and Marcus North.

Marsh made his debut for WA in 2001 while still a teenager and in his second season, he made 119 against a full-strength New South Wales, earning the praise of Steve Waugh and convincing many present in Newcastle that he was destined for greatness. In 11 summers since then, he has made another seven first-class tons.

Marsh has a long history of disciplinary problems in WA. He was among the players suspended during Perth Scorchers' 2012 Champions League campaign. Previously, in 2007, he and state team-mate Luke Pomersbach were suspended after a boozy night. Marsh says: "I had a few distractions away from cricket as well, which you just can't have when you're playing for Australia. I knew I had to change my lifestyle."

Langer is not Marsh's only ally among the powerful and influential in Australian cricket. The national team coach, Darren Lehmann, is an avowed fan of Marsh's talent, having coached him for King's XI Punjab in the IPL as recently as last year. "He's backed me in a fair bit since he's been with the Australian team. He's a fantastic coach and he's been great for Australian cricket," Marsh said.

Numerous senior members of the Australian Test team are convinced that Marsh is the best batsman outside of the XI. Much of this conviction stems from his debut series in Sri Lanka in 2011, when Marsh made 141 on debut in the second Test, in Pallekele, and followed up with more runs in the third match, in Colombo. Brad Haddin is among the believers. "It was nice to be there at the end [of Sunday's ODI] with Brad Haddin," Marsh said. "He's been very good to me as well, whenever I've come back into the team he's been really supportive."

They have also been swayed by Marsh's proficiency in short formats, whether it be his success in the IPL or consistent scoring for Australia whenever chosen in the ODI team. In the domestic limited-overs tournament that commenced the season, Marsh struck 430 runs at 86, with one century and four other scores over 50. His time in the ODI team has been interrupted largely by injuries - chronic hamstring trouble has affected Marsh for much of his career.

After Sri Lanka, Marsh played his only Test match in South Africa, at Newlands in Cape Town. In the first innings on a lively pitch, he reached 44 in the company of Michael Clarke before being trapped lbw. His back then seized up and he made a duck in the second innings before missing the rest of the tour. "In that first Test match that he played, Australia eventually were bowled out for a very small total," John Inverarity, the national selector, said. "But in that first innings, Michael Clarke made a century and Shaun played exceptionally well against that attack."

Since becoming coach of WA, Langer has made demands of Marsh, trying to reshape his mental approach while also making a few technical adjustments. He has also pushed the WA squad hard, not forgiving them for the tendencies towards indiscipline that have led to more than a decade of under-performance. "We haven't won anything in WA for a long period of time and I think you've got to actually earn the right to go out and enjoy yourselves and have fun," Marsh said. "Once you start winning games of cricket and winning finals, then you can start to do that a little bit more."

Marsh is aware of how fortunate he is to be granted yet another chance, having done very little in pure performance terms to warrant it. At the age of 30 he has had more chances than any Australian cricketer should have a right to, and acknowledges that the enormous degree of selection faith he has been given must somehow be repaid. "They've obviously shown a huge amount of faith in me," he said. "It'd be nice to reward them with a few runs in South Africa if I get a chance to play."

Marsh is not entirely sure why he has been thrust back into Test contention once more, and could barely believe it when Inverarity called him. But in addition to Langer, Lehmann, Haddin, Clarke and others, there is the other benefactor to be considered. Shaun Marsh's dad is Geoff "Swampy" Marsh, the former Australia vice-captain and opening batsman, who was on hand to present his son with a Test cap in Sri Lanka in 2011. Whatever Marsh has been, and whatever he may become, he will always be SOS, the son of Swampy.

Daniel Brettig is an assistant editor at ESPNcricinfo. He tweets here