Republic of Ireland manager Vera Pauw says it was "devastating" having to make 75 phone calls to players when deciding on her 31-strong World Cup training squad.
Pauw added she had called the omitted players a second time and that the Football Association of Ireland will provide support to those who miss out.
The final 23-player squad, plus three reserves, will be named on 29 June.
"I am very much aware that I have broken dreams," said Pauw.
"It's elite sport, you have to make choices. I wish I could bring them all but we can't," Pauw added, stating she "had to stop for a moment" because the calls to players were so difficult.
"Believe it or not, with all the clubs and everybody, on one day I had to make more than 75 phone calls.
"The shift was done, and I've called every single player again to see how they are doing.
"We have offered them support because it can have a real impact on their moods and their way forward.
"It's devastating and It will have an impact on careers, also. We have not been taking it lightly and every single player was on the table."Mannion out as Pauw names World Cup training squad
'Tightest decisions still to come'
Dutch manager Pauw said "the tightest decisions" are yet to come when narrowing down her final squad ahead of the announcement on 29 June.
After naming 31 players in her training squad, and with the unnamed Aoife Mannion still a doubt but likely to be included if fit, up to nine players will be cut for the final 23 to make the World Cup.
However, an additional three players will travel to Australia as reserves to be injury back-up ahead of the tournament and also to help with training and preparation.
The Republic's first game is against co-hosts Australia on 20 July before matches against Canada and Nigeria in Group B.
"After all the talks and analysis that we have done, we are sure about this squad," Pauw added on the 27 players selected.
"Every player that comes into the camp has the same chances [to make the final squad]. We have to make our final decisions on the basis of what you show in camp.
"That is for everybody. Of course, we all know there are a few that are pretty sure about their place, but for any other player that is on that fringe of the squad, it is completely open.
"The proof of that is Lucy Quinn. For the USA games she was coming in off a standby list. The penny needs to drop on the tactical part and, with her, it dropped just in time.
"She was player of the match and, at her club, she was a four-time player of the match.
"It can happen like that with any player and we will stay open until the last second of the decision."