[4] In 2011, after playing in the 2011 Eurobasket tournament, he was loaned to Bàsquet Tarragona 2017, team of the Spanish second-tier league LEB Oro.

[11] On 7 January 2015 he was loaned to Leeds Force of the British Basketball League[12] and made his debut three days later, scoring 16 points and 6 assists shooting 6-17 from the field on a loss against Plymouth Raiders.

[21] On 5 July 2018, Van Oostrum signed with New Heroes Den Bosch of the Dutch Basketball League (DBL) and the FIBA Europe Cup.

[22] On 3 October, Van Oostrum made his debut with Den Bosch in the FIBA Europe Cup qualifying game against Balkan, scoring 17 points and recording 9 rebounds and 3 assists.

[24] In August 2019, van Oostrum signed a two-month contract with CBet Prienai of the Lithuanian Basketball League (LKL).

[26] On 4 December 2019, Van Oostrum returned to the Netherlands to sign with Landstede Hammers of the Dutch Basketball League (DBL).

On 23 November 2020, Van Oostrum was sent on loan to Peñas Huesca for four weeks because the DBL had been suspended due to the COVID-19 pandemic.

[30] On 11 December 2023, Van Oostrum joins RANS Simba Bogor of the Indonesian Basketball League (IBL).