Speaking at a press conference before Chelsea's midweek WSL clash with Tottenham, Hayes said: "I will often say to the players that you have to put your career first and Millie was putting her body in a situation where, if she didn’t look after it…careers are short. I advised her to really prioritise a little longer term instead of just constantly playing in pain. That's been tough for her, a long time out, and hasn't been smooth running.
"That's why I think probably most managers get frustrated when [journalists] ask, 'Who's injured?' and we say, 'They are and it might be a week'. All of a sudden it’s three weeks or four weeks, or a month, or two months. It's not because we play games with you, this is the nature of what happens coming back from rehab and Millie's was certainly not straightforward.
"I'm happy for her that she's back [but] I still think she has to build progressively. It's a testament to her character, she's always been a leader in our dressing room and one that's given everything to Chelsea and everything to me in my time here."