What made it such a shock is not just that John is so young — he turned 18 only last month — but that he has been suffering from a long-term pelvic injury and the only match he has played this year was the Scottish Schools cup final when he captained Dollar Academy to victory, scoring the opening try. John was due to play for Glasgow Hawks 2nd XV last weekend but the plans were scuppered by a slight flare-up of his injury.
Obviously now desperate to get his first outing of the season, John was heading to the phone to plead with Peter Wright, the coach at Glasgow Hawks, for an outing this weekend in the Hawks' BT Cup match against St Andrews University.
"He's an absolutely outstanding player, he has a lot of talent," said Scotland coach Matt Williams in today's Times. "What we are doing is bringing him in and giving him time with the squad and if he makes the bench, that will be a huge bonus.
"What we need to do with these young guys is find them and educate them; the only way to teach them to play international rugby is for them to actually play international rugby."
John told today's Scotsman: "It is very strange. It's a great privilege and a massive confidence boost to be selected by Matt, but it's a bit surreal to be training with the national squad and driving here with Gordon Bulloch to a national squad announcement.
"I've obviously got a lot to learn, and I'm learning a lot with every training session, and guys like Donnie Macfadyen are very good at helping you out. The intensity of training took me aback, but it's a good thing and it makes you step up to the plate. Coming from school where a lot of guys were doing it for fun to this, where it is these guys' life, was incredible and I felt a bit out of my depth at first, but I've got used to it and am enjoying being part of the squad."