Scottish rugby’s front-row crisis deepened yesterday as it emerged that Zander Fagerson has had a freak accident in the gym while Fraser Brown has been ruled out indefinitely while his head injury problems are examined.

With seven international props and hookers currently unavailable at Edinburgh, the loss of two more members of the national team’s autumn Test series squad could not have happened at a worse time.

In Fagerson’s case he hurt himself just days after claiming the relatively rare accolade for a tighthead prop of picking up a man-of-the-match award following Glasgow’s derby win over their Inter-City rivals last weekend.

Head coach Dave Rennie’s obvious exasperation was wholly understandable in that context as he revealed that thee 21-year-old would be out of action for at least eight weeks.

“It is his foot, and from a scrummaging viewpoint a lot of load goes through that. The guide is 6 to 8 weeks, but for a front row player it can be longer,” said Rennie.

“He knocked something over and it fell on his foot in the gym. It is one of those frustrating injuries.”

Nor was it the only strange injury to afflict a front five forward at the club this week with his fellow 21-year-old front five man Scott Cummings, who scored a try in the first of the derbies, also looking at a lengthy lay-off.

“The boys were mauling and he got his finger caught in a jersey. He has a fracture above his knuckle. We're looking at 6 to 7 weeks hopefully,” said Rennie.

The club has also had to accept that summer signing Callum Gibbins, who made a major impact in the early part of the season, could be out for three months having had to accept that his achilles tendon injury will not heal without surgery.

The situation regarding Brown is meanwhile more fluid following the latest in a series of head knocks.

While he seems to have made a full recovery, after having to leave the field during Saturday’s match, it is the number of problems he has had that is causing concern.

“We've just been really conservative around Fraser,” said Rennie.

“As often happens, he has no symptoms. He has completed all the protocols, but he has had two or three head knocks this season already. We just want to find out a bit more about why.

“If you get a knock on the head he seems okay but if he gets a knock on the jaw he ends up getting knocked out.

“He comes back reasonably quickly and we just want to do a bit of research around this. We’re not going to rush him back in until we know a bit more.

“There's not an enormous amount of science around concussion. We are talking to other people in other fields about this to try and maybe work out what's going on.”

Rennie admitted that there has been a radical change in the way concussions are looked at within the game since his own playing days.

“There is no doubt that we were pretty reckless when I was playing. If you got a knock on the head you jumped out the next week; there were no protocols to go through at all.

It's quite difficult. You need at least a five-day stretch, and sometimes there's just not enough time in the week to tick every box and get a player back out there.

“The key is not to rush things. If a player has had multiple head knocks you have to be cautious around that. That's what we're going to do with Fraser.

“He seems fine but we have to look at why this is happening. With most players who have symptoms, it takes a while, if they have a number of knocks, to get over it.

“But Fraser ends up with no symptoms at all and bounces back immediately. We just want to find out what's happening and we need to take our time with that.”