Tom Smith's confirmed departure gives the selectors their biggest headache as there are no obvious successors but Hadden believes that 24-year-old Euan could just be the man.
"I worked with him way back at Scotland youth level and I said he could go all the way to the very top and he still has all the qualities to do just that," said Hadden on the Sporting Life website.
Glasgow stand-off Dan Parks was also named in the squad despite having a difficult RBS 6 Nations Championship campaign.
"Dan is a good stand-off and played well for Scotland and has played consistently well for Glasgow but he needs to try to prove his worth."