Palmer made 15 appearances for MU Women in the 2018/19 season - her debut came in August 2018 in the Continental Cup fixture against Reading - and scored her first goal for the club during a 5-0 win against Lewes on the final day of the season.
Casey Stoney said: “Aimee is a great young talent and progressed well with us last year; this loan move will be really beneficial for her and we wish her the best of luck with Sheffield United.
“They finished the season in good form and will be looking to push on in the Championship so it will be a perfect opportunity for Aimee’s development.