Well, we know why he was out there. Australia sent its official 12th man, James Pattinson, to Perth to play the final two days of a Sheffield Shield match yet strangely no-one has questioned the impact of that decision on the integrity of the best domestic cricket competition in the world.
So with the Shield round under way, and no grade cricket in Adelaide on the test weekend, the Australians had three local district cricketers man their rooms.
The Australians didn't want to chuck the locals on to field before crowds of more than 40,000 people in cricket's inaugural day-night test.
So they opted for Baldwin, who has played for Victoria's second XI - and also fielded for the Australians in tour games in the United Arab Emirates and South Africa, where he bowled an over.
"Grant has obviously played second XI cricket for Victoria, he has fielded for us before on tours," Test paceman Josh Hazlewood said.
"We have got three young guys here who haven't played first-class cricket.
"But we thought Grant was probably the best option ... it's quite a pressure situation out there in front of 40,000 (spectators), so with those other three guys not playing first-class cricket before, we thought it was the best case."
Baldwin's misfield cost three runs - and, not incidentally, it came after Mitch Marsh failed to get a finger to a hot caught and bowled chance.
Perhaps imagining the furore if the hosts lose the Adelaide Test by three or less runs, Baldwin is now being replaced. On Sunday, Sam Raphael - a 28-year-old who has played 14 first-class games for South Australia - will field for his country as Starc's replacement.