Southgate's coach, Neil Hawgood, has spent the whole season trying to convert Giles into an all-round field player now that he is no longer allowed to be substituted on to take penalty corners. Finally his patience has snapped.
Another Southgate casualty is the Welsh international, Andrew Grimes, in a game which is their last chance to achieve something out of the season. Teenagers John Grice and Jon Peckett come into the squad.
Cannock will be missing their England centre-half Justin Pidcock who was injured at Reading last weekend and also Martin Jones who will be captaining Repton in the final of the RAF Careers Youth Under-18 Cup final. Pidcock came out of hospital on Thursday after a successful operation on his injured knee.
Reading, after their two outstanding performances in the Premiership play-offs last weekend, will start favourites to win the second semi-final away to Old Loughtonians.
In today's women's EH Cup semi-finals at Milton Keynes a depleted Slough side will play Chelmsford Highway while Olton Terraquest face Fyffes Leicester.
Slough will be without their influential Irish international Sarah Kelleher in their midfield and defender Ali Burd, who popped up last weekend to score both their goals which put them through to the League Championship final against Clifton Scottish Life. There is also considerable doubt about captain Sue Chandler who missed last week's game.
Chelmsford, who have already achieved promotion into the Premier Division, will be at full strength.
Leicester's recent good form will give them a lot of confidence along with the return of the England striker Purdy Miller who will be available for her first full game of the season after returning from injury. With Olton's blend of youth and experience it would be a brave man to predict the winner.