Wing Seymour sustained a neck injury during Scotland's 55-6 defeat to South Africa on Saturday, ruling him out of action at Glasgow 2014.
But Scotland sevens head coach Stevie Gemmell insists the inclusion 22-year-old Hogg could prove a blessing in disguise.
"It's disappointing to lose Tommy but I'm delighted to be able to bring in a player of Stuart's calibre into our squad," Gemmell told the Daily Record.
"Although he has not yet played international sevens he comes from a background in the Borders that has been heavily influenced by the game.
"His game understanding along with the skills he has developed as a professional will I am sure prove a strong addition to our existing playing group. I'm excited about him joining the squad and contributing to a successful performance at Ibrox."