The revolt by the players followed a kiss on the lips of player Jenni Hermoso by the country's football federation (RFEF) boss Luis Rubiales after Spain won the World Cup.
She disputed his insistence the kiss was consensual, sparking a national debate about macho culture in the sport.
Another source close to four other players told Reuters they were seeking legal advice to decide whether to report to the squad on Tuesday, afraid of the threat of punishment.
"They come from being world champions, they love the profession and I know they will be here with us tomorrow."
An original group of 81 players had called the boycott in the wake of the furore over Rubiales' kiss.
Persons:
Montse Tome, Jenni Hermoso, Luis Rubiales, Hermoso, Mapi Leon, Patri Guijarro, Jorge Vilda, Tome, Jenni, Fernando Kallas, Emma Pinedo, David Latona, Andrei Khalip, Charlie Devereux, Philippa Fletcher, Ken Ferris
Organizations:
Players, Spain, Reuters, Sports, Sweden, UEFA Nations League, Thomson
Locations:
Spain, Sweden, Switzerland