Assistant manager James McFadden says players who withdrew from Scotland's summer tour have harmed their chances of earning selection again.
A series of call-offs led to manager Alex McLeish using nine previously uncapped players in the end-of-season defeats by Peru and Mexico.
"I never knocked it back as a player," said McFadden, who scored 15 goals in 48 internationals.
"I can't believe there were players that couldn't make the trip."
McFadden, 35, continued: "They've harmed [their chances] in that aspect but they've also harmed it in the players that have come in and done well in their place.
"It's a new coaching staff, new campaign coming up and we're looking for players that want to go and play for Scotland, but are also good enough, and if we don't get a chance to see them, how can we judge them?
"The ones that came in did very well and it'll be difficult for the ones that pulled out or weren't there to get back in."
'Lewis Stevenson was excellent'
Celtic's Kieran Tierney was rested for the trip, while fellow left-back Andy Robertson missed the fixtures as he represented Liverpool in the Champions League final.
McFadden singled out Hibs' Lewis Stevenson and Kilmarnock's Stephen O'Donnell for praise in defence.
"Lewis Stevenson was excellent, he had a fantastic season and played really well," McFadden told BBC Scotland. "Stephen O'Donnell played two 90 minutes, and it was a position we were looking for players to step up and he certainly did that.
"We had a double-header there where we were missing Andy Robertson and Kieran Tierney, and Lewis Stevenson showed he can go in and fill in no problem.
"[New Sunderland signing] Dylan McGeouch had his chance and did really well. [Celtic midfielder] Lewis Morgan coming on in the Peru game, as soon as he came on, his first touch, he's eliminating players and he did well in the Mexico game as well."
'It was a fantastic experience'
McFadden also defended the merits of the tour - which some critics labelled a pointless exercise - arguing the experience will benefit McLeish's players for their Nations League campaign, which begins in September.
When asked if the dissenting voices had been proved wrong, the former Everton striker replied: "I think so, the organisation and timing maybe wasn't great, but it was a great experience, playing in the Azteca Stadium sold-out, playing against Peru who were going to their first World Cup in 30-odd years, the atmosphere, the feeling in the country in general was incredible.
"We played and competed well against two teams who were at the World Cup, Mexico who did really well, beat Germany, few fantastic players, and I think overall we can say it was a success.
"All right, we didn't win any of the games, but considering you're against two teams going to the World Cup, it's their last game before they go, it's a sell-out, the atmosphere was electric, they want to go and impress, and we had a lot of players that called off or weren't in the initial squad, and to go and give the account we did, we can be proud of that.
"We've found players that have given us a headache which is fantastic but the bigger picture is that we went an did well in conditions that were difficult. Especially in the Azteca, the altitude, the heat, the fact we had quite a small squad.
"It was a fantastic experience and something we'll certainly draw on going into the qualifying campaign in the Nations League."