Steven Reid has told all potential Scotland players to be ready for action ahead of the Euro 2020 play-off against Israel.
The keenly awaited semi-final takes place at Hampden Park on March 26, with the winners facing either Serbia or Norway away in the final, which comes five days later.
National team boss Steve Clarke hopes the injured trio of Kieran Tierney, Scott McTominay and John McGinn will have recovered in time and that there will be no further disruptions to his squad as he seeks to lead Scotland to the finals of a major tournament for the first time since 1998.
By way of showing how things can quickly change in international football, Scotland coach Reid, now 38, recalled how he got a late call-up to the Republic of Ireland squad for the 2002 World Cup, with only four caps to his name, and managed to make an appearance on the biggest stage of all.
The former Blackburn and West Brom player said: "For me, it was Mark Kennedy getting injured for Ireland.
"I wasn't even in the squad to go to the World Cup.
"Mark Kennedy got injured in Niall Quinn's testimonial game the night before we were due to meet up.
"I got my opportunity and I was the first substitute on the pitch against Cameroon in the first group game.
"It was an opportunity for me, and an opportunity for one or two others, definitely.
"If there is an injury for one then hopefully one or two can step up to the plate.
"It is still the highlight of my career being involved in a tournament like that.
"I thought I would be playing in another one in four years but it never happened again.
"This might be a once-in-a-lifetime opportunity for these players.
"Hopefully everyone stays fit and those that are injured get back fit as soon as possible.
"But plans need to be in place if we do get those injuries, you are not plucking one or two players out of the air.
"Someone might hit form, get back into their team, be playing well at club level and someone might drop out.
"You have to be monitoring all of them."
