The uncapped player had been called up by England boss Gareth Southgate for international friendlies against the Netherlands and Italy, but a long-standing knee problem has put paid to his World Cup hopes.
Mawson underwent surgery on Monday, and although he will definitely be sidelined for the international tournament, the defender is expected to be fit ahead of next season.
Despite Swansea's relegation to the Championship, the 24-year-old had produced some quality performances over their season and was widely tipped for a seat on the plane to Russia.
Mawson enjoyed a particularly active season with the Swans having featured in every single Premier League match with the club either on the bench or in the starting lineup in this campaign.