She previously played for ADO Den Haag, AFC Ajax, Manchester City, West Ham United, and Fiorentina.

[2] Middag also won the Eredivisie and KNVB Women's Cup with ADO Den Haag.

[5] She made her first start for the club on 2 July against Aston Villa and scored a goal in the first half of match.

After nine months out, Middag made her return on 21 March 2018, entering as an 81st minute substitute in a Champions League quarter-final against Linköpings FC.

[9] However, Middag but did not play during the 2018–19 season after sustaining a second ACL injury picked up while on international duty in summer 2018.