The City trio are part of a group of 24 that will face Czech Republic, Albania, Kosovo and Slovenia next month.
England currently sit in second place with 16 points from six matches but Lee Carsley's team know they have two games in hand on leaders Czech Republic.
All three City players involved spent the 2021/22 season on loan.
Midfielder Doyle, who has played three of England's six qualifiers so far, featured 19 times for Championship side Cardiff City.
Defender Harwood-Bellis began the season in Belgium with Anderlecht, where he played 16 times before 22 appearances at Stoke City in the second half of the campaign. He is yet to miss a minute of England's qualifiers.
Goalkeeper Trafford played 11 times for Accrington Stanley before a further 22 games for Bolton Wanderers, both in League One. Should he feature, he will make his England U21 debut.
We'll provide regular updates of how our trio are getting on right here on the Man City app.
The 2023 European Under-21 Championship will be played between 9 June and 2 July 2023 in Georgia and Romania.
- Czech Republic v England, Stadium Strelecky Ostrov, 3 June (5pm)
- England v Albania, Technique Stadium, Chesterfield, 7 June (7.45pm)
- Kosovo v England, Fadil Vokrri Stadium, 10 June (7pm kick-off);
- England v Slovenia, John Smith’s Stadium, Huddersfield, 13 June (7.45pm)
Full England U21 squad: Joe Bursik, James Trafford, Carl Rushworth; Max Aarons, Charlie Cresswell, Taylor Harwood-Bellis, Levi Colwill, James Hill, Luke Thomas, Ben Johnson, Djed Spence; Ryan Sessegnon, Tommy Doyle, Jimmy Garner, Morgan Gibbs-White, Jacob Ramsey, Curtis Jones, Harvey Elliott; Flo Balogun, Anthony Gordon, Angel Gomes, Keane Lewis-Potter, Emile Smith-Rowe, Cameron Archer