Wales will be without captain Aaron Ramsey for the friendlies away to Gibraltar on Thursday, 6 June and the trip to Slovakia three days later.
The midfielder, 33, played just 13 times for Cardiff City in an injury-hit 2023-24, while he featured only twice during Wales’ European Championship qualifying campaign.
Veteran goalkeeper Wayne Hennessey is also absent from the 25-man squad with what Wales manager Rob Page says is a "significant injury".
With Ramsey, who has scored 21 goals in 84 Wales caps, left to concentrate on regaining his fitness, Page has selected five uncapped players - including Liverpool forward Lewis Koumas.
The 18-year-old is set to follow his midfielder father Jason as a full Wales international, while there is also a call for another teenager in the shape of 17-year-old Leeds United midfielder Charlie Crew.
Coventry City's Jay Dasilva and fellow defender Fin Stevens, who has impressed on loan with Oxford United from Brentford, plus Wolverhampton Wanderers goalkeeper Tom King are the other uncapped players.
King, Danny Ward and Adam Davies are the three keepers chosen in the absence of Hennessey.
The 37-year-old, capped 109 times, has been a regular for Wales since making his debut in 2007 and been part of three major tournament final squads, but did not feature for Nottingham Forest this past season.
There is also no place for Oxford forward Mark Harris, despite his 19 goals helping them clinch promotion to the Championship via the play-offs.
Leeds winger Dan James is included despite suffering a head injury in their Championship play-off defeat by Southampton at the weekend.
Likewise, Tottenham defender Ben Davies is named despite missing the tail-end of the season with a calf injury.
Midfielder David Brooks was also injured in the Championship play-off final, but he has not been included.
Harry Wilson, who is injured, Neco Williams, Morgan Fox and Dylan Levitt do not feature.
Page suggested earlier this month that he would leave Ramsey out so he could concentrate on getting fit for next season.
“He is our captain at this moment in time, he wants to get his body into a position where he is fit and can cope with the demands of Championship football, which is not easy," Page had told BBC Wales Sport.
“If he can do that I have no doubt he will carry on.”
The two friendlies are part of Wales’ build-up for their opening Nations League fixture at home to Turkey on Friday, 6 September, before they travel to face Montenegro on 9 September.
Wales will be away in Iceland on Friday, 11 October, with the reverse fixture against Montenegro the following Monday.
Page's side then travel to Turkey on Saturday, 16 November before concluding the group at home against Iceland on Tuesday, 19 November.
Wales squad
Goalkeepers: Danny Ward (Leicester City), Adam Davies (Sheffield United), Tom King (Wolverhampton Wanderers).
Defenders: Connor Roberts (Leeds United - on loan from Burnley), Fin Stevens (Oxford United - on loan from Brentford), Joe Rodon (Leeds United - on loan from Tottenham Hotspur), Chris Mepham (Bournemouth), Ben Cabango (Swansea City), Joe Low (Wycombe Wanderers), Ben Davies (Tottenham Hotspur), Jay Dasilva (Coventry City).
Midfielders: Ethan Ampadu (Leeds United), Jordan James (Birmingham City), Josh Sheehan (Bolton Wanderers), Charlie Savage (Reading), Charlie Crew (Leeds United), Brennan Johnson (Tottenham Hotspur), Wes Burns (Ipswich Town), Rubin Colwill (Cardiff City), Daniel James (Leeds United), Rabbi Matondo (Rangers).
Forwards: Nathan Broadhead (Ipswich Town), Kieffer Moore (Ipswich Town - on loan from Bournemouth), Liam Cullen (Swansea City), Lewis Koumas (Liverpool).