Abroad, he had spells at Motherwell in the Scottish Premier League and Marítimo in Portugal's Primeira Liga, playing 174 total games for the latter and scoring 19 times.
He scored a career-best seven goals in 28 games in his second full season to help the Steelmen narrowly avoid relegation from the Scottish Premier Division,[2] and subsequently returned to the Eredivisie with Utrecht.
[6] After helping them finish fifth – a place conquered in the last round with a 2–1 away win against Vitória de Guimarães, who were leapfrogged in the process – and qualify for the Europa League,[7] his contract was renewed for a further year.
[10][11] Van der Gaag took a temporary leave of absence in late September 2013 due to heart problems, after feeling unwell during a league game against former side Marítimo (1–0 home win).
[14] After spending the 2015–16 season back in his country with FC Eindhoven, in the Eerste Divisie,[15] van der Gaag moved to the top flight and successively coached Excelsior[16] and NAC Breda.
[20] On 26 November 2023, in a Premier league match against Everton at Goodison Park, with Erik Ten Hag suspended, Van der Gaag was the coach on the sidelines as Manchester United won 3-0.