Sons of former Australia player Geoff Marsh, Shaun and Mitch will also become only the fifth set of siblings in the Australian history to play in the same Test side.
Before the Waughs (Steve and Mark) and the Chappells (Ian and Greg), the Gregorys (Ned and Dave) played in 1877 followed soon after by Charles and Alec Bannerman in 1879.
"They've worked hard and they're reaching their dream," Geoff, the veteran of 50 Test matches, was quoted as saying by 'Daily Telegraph'.
"Shaun's had a bit of bad luck with his injuries - the timing of his injuries. He's been playing for Australia and done hamstrings, and broken down at the start of this year with an elbow injury. So he's had a bit of bad luck with injuries.
"But hopefully from now on he gets a good run and grabs the opportunity. Mitch has had a couple of injuries, but he's at that age where with his bowling there's a lot of injuries around players of that age. Hopefully, touch wood, he's going to pull through," Geoff said.