MacDonald, the leading goal-scorer during the Olympic build-up programme, is one of three players to lose their place from the squad who qualified for Atlanta in Cape Town last November. Lucy Cope and Scotland's Diane Renilson also drop out.
Britain's manager, Jenny Cardwell, said: "We felt that the chosen strikers had the edge on speed and versatility," referring to the Slough pair of Mandy Nicholls and Anna Bennett.
Leicester's Kath Johnson and Jo Mould and Hightown's Tina Cullen are the three additions to the squad from Cape Town. Johnson, who returned to international hockey this year after the birth of her first child, will add experience, and with her tenacious tackling seems certain to line up in the centre of the back four with Karen Brown. They should provide a formidable partnership.
Eight of the squad won bronze medals in Barcelona, and for three, Brown, Jill Atkins and Jane Sixsmith, Atlanta will be their third Olympics.
Britain play the Pan-Am champions, Argentina, at Lilleshall on 21/22 May.
GREAT BRITAIN WOMEN'S OLYMPIC SQUAD: H Rose, J Sixsmith, M Davies (Sutton Canada Life), K Brown, M Nicholls, A Bennett (Slough), J Thompson (Ipswich), J Atkins (Bradford Swithenbank), K Johnson, J Mould (Balsam Leicester), T Miller (Clifton), T Cullen, C Cook (Hightown) (all England); S Fraser, P Robertson (Bonagrass Grove), R Simpson (Edinburgh Ladies) (all Scotland).Reuse content