Hayes was forced to skip Friday’s pre-match press conference. with her assistant, the team’s general manager Paul Green, fielding questions from the media.
He said: “We are hoping Emma is going to be back tomorrow, it is just a viral illness so hopefully she can shrug it off.
“She wasn’t feeling the best during the second half of the Brighton game and still felt a miniature bit under the weather yesterday. So hopefully she’ll gain recovered today and be back in for training tomorrow.
“We’ll gain to wait and see, hopefully she’ll be marvelous to recede. If she isn’t, Denise (Reddy, his fellow assistant) and I will seize the team as we did earlier in the season. Emma has still got access to the training footage and there’ll be regular communication if she wasn’t to construct it on Sunday, as we had earlier in the season.
“She’ll gain a direct earpiece to Denise on the sideline but we’re hoping she’ll be back if not tomorrow then certainly on Sunday.”
Green and Reddy oversaw the first team for six matches – all victories, including a 3-1 win at United – after Hayes underwent an emergency hysterectomy in October.
Sunday’s contest at Kingsmeadow sees the league’s top two recede head to head, with United currently a point clear of champions Chelsea having played a game more.
Additional reporting by Press Association.