text: Croker starts at hooker for the hosts at Twickenham, with Amy Cokayne dropping to the bench.
  Ciara Griffin is handed her first Six Nations start at flanker for Ireland, while Paula Fitzpatrick moves to number eight and Heather O'Brien to the bench.
  Experienced fly-half Nora Stapleton comes in for Nikki Caughey, who will provide back-up from the replacements.
  Ireland, led by Tom Tierney, defeated Wales 21-3 in their opening fixture, but went on to lose 18-6 against France in Perpignan.
  England won their opening two fixtures, against Scotland and Italy.
  "Ireland is going to present a tough challenge this weekend and there will be no margin for error," said England's lead coach Scott Bemand.
  "Recent history testifies that our games have been fiercely contested and, as a group, we are very excited to play at the home."
  Tierney added: "While the result in France didn't go our way, I thought there were a lot of positives to take from that game and we will be looking to carry them into this fixture.
  "We made too many unforced errors in Perpignan, so if we can rectify that I think we have got a very good chance on Saturday.
  "Twickenham is a special place to play, so it will be a great experience for the girls, but it is important that we go there looking to perform and hopefully come away with a result."
  England women: Katie Mason (Bristol); Lydia Thompson (Worcester), Lauren Cattell (Saracens), Ceri Large (Worcester), Lotte Clapp (Saracens);  Amber Reed (Bristol), La Toya Mason (Darlington Mowden Park); Rochelle Clark (Worcester), Emma Croker (Richmond), Vickii Cornborough (Richmond);  Abbie Scott (Darlington Mowden Park), Emily Braund (Lichfield); Harriet Millar-Mills (Lichfield), Izzy Noel-Smith (Bristol),  Sarah Hunter (Bristol)
  Replacements: Amy Cokayne (Lichfield), Heather Kerr (Darlington Mowden Park), Bee Dawson (Wasps), Tamara Taylor (Darlington Mowden Park), Poppy Leitch (Bristol), Bianca Blackburn (Worcester), Ruth Laybourn (Darlington Mowden Park), Leanne Riley (Richmond)
  Ireland women: Niamh Briggs (Munster); Elise O'Byrne-White (Leinster), Aine Donnelly (Leinster), Sene Naoupu (Connacht), Mairead Coyne (Connacht); Nora Stapleton (Leinster), Larissa Muldoon (Skewen); Ruth O'Reilly (Connacht), Cliodhna Moloney (Leinster), Ailis Egan (Leinster); Sophie Spence (Leinster), Marie Louise Reilly (Leinster), Ciara Griffin (Munster), Claire Molloy (Bristol), Paula Fitzpatrick (Toulouse).
  Replacements: Zoe Grattage (Munster), Fiona Hayes (Munster), Fiona Reidy (Munster), Ciara Cooney (Leinster), Heather O'Brien (Toulouse), Mary Healy (Connacht), Nikki Caughey (Ulster), Jackie Shiels (Richmond).
target: England have brought in Emma Croker and have Ireland made two changes for Saturday's Women's Six Nations game.