Thompson's team-mate, John Houston, is also added to a squad which has yet to make the quarter finals of the main cup competition this season.
Reaching that stage will be Scotland's first target when the penultimate leg of the HSBC World Sevens Series gets under way with group matches at Scotstoun Stadium on Saturday. Shiel's side have been drawn in Pool D with Wales, South Africa and Russia.
"Our aim is qualify for the quarter finals, because we want to be playing against the best sides in the world," said Shiel. "Until we're doing it consistently it's a hard step to achieve.
"I've selected players on their current form and in terms of how they are performing in their position so we have the strongest team and right balance across the field.
"Usually at this time of year we see an influx of professional players. It's not the case this time, because our regular players have equipped themselves well and it's a case of continuing to develop their skills.
"Jim and John are in because they both have an understanding of the circuit and have fantastic sevens knowledge. We also have Scott Riddell and Stuan Dewar back in the squad.
"Scott always performs to the highest level, while Struan has had a tough season with injury but has worked hard to get back to full fitness. His ability and experience are hugely important to our performance."
Tickets are selling briskly, with less than 9000 of the 30,000 still available.