She became the first player to reach 100 appearances for United's women's team last season, while she also worked in the club's marketing department.

Heckingbottom said the news of Cusack's death had "knocked" him.

"First and foremost, everyone's thoughts are with Maddy's friends and family," he said.

"She has been a big part of everything in my time here. She's a senior figure in the women's team and in the media team. It's tough and we need to make sure everyone is OK at the club and we all support each other.

"There are plans and discussions [for a tribute] going off now but we want to be respectful to Maddy's family to make sure they are involved. As much as we want to show our respects we want to make sure the family lead on that.

"Steve [Bettis - United's chief executive] called me yesterday and it knocked me back a bit, I'll admit.

"As much as we preparing for a huge game and wanting to get on with everything it has affected a lot of people and in different ways.

"Maddy has been so close to so many people at this club. We look after everyone here but, I'll say it again, it's about her family."

The cause of Cusack's death has not been announced.

Before joining the Blades in 2019, she also played for Birmingham, Aston Villa and Nottingham Forest.

Her former team-mate at Villa, Chloe Hudson-Jones, told BBC Newsbeat Cusack "had determination that's rarely seen in the game".

"She was one of those players that would have been horrible to play against. But she was the best team-mate and person to have on your team," she said.

"She would run through brick walls to help her team."

She added: "If we ever did fitness tests, the challenge was to always try and beat Maddy.

"We used to joke she was a little bit clumsy and she'd make us laugh. But she was such a bubbly character."

This weekend's FA Women's National League fixtures between Newcastle United and Burnley, and Nottingham Forest and Liverpool Feds, have been postponed due to Cusack being a former team-mate of several of the players due to be involved.

All remaining fixtures in the league will hold a minute's silence before kick-off.