Middag joined ADO Den Haag in 2011. During her debut season, she scored ten goals in eighteen matches.[2] Middag also won the Eredivisie and KNVB Women's Cup with ADO Den Haag.[3]
Ajax
Middag signed with AFC Ajax in 2012. She made 94 appearances for the club, during which she scored 15 goals[4] and again won the KNVB Women's Cup in 2014.[3]
Manchester City
On 3 June 2016, Manchester City announced they had signed Middag.[4] She made her debut for the club after being brought off the bench against Liverpool on 30 June and was voted Player of the Match by the Official Supporters Club.[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.[6] In May 2017, Middag suffered an ACL injury during a Spring Series match against Reading. 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.[7] Middag left Manchester City at the end of the 2017–18 season upon the expiry of her contract having made three appearances in her final season with the team.[8]
West Ham United
On 14 July 2018, Middag joined West Ham United.[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.[10] Initially taking the #6 shirt, Middag changed to #23 ahead of the 2019–20 season having never worn #6. This was partly because the number had already been retired by the men's team in honour of Bobby Moore but also because it represented Middag's "fresh start" with the team following her long-term injury.[11]
In August 2021, Middag joined Scottish club Rangers.[13]
International career
During 2010 and 2011, Middag made 17 appearances for the Netherlands U19 team.[14] She broke into the senior squad in 2012,[15] in a 2–1 friendly defeat by France. A member of the 31-player provisional squad for UEFA Women's Euro 2013, she was not selected for the final 23-player list.[16] Middag was part of the Netherlands squad in the 2015 FIFA Women's World Cup.
International goals
Scores and results list the Netherlands goal tally first.[17]