[2] After the club suffered relegation from the Eredivisie in the 1977–78 season,[3] he moved to Den Haag alongside Ton Wickel.

[4][5] This was subsequently denied by De Visser, who stated that Maradona was already hugely popular in Argentina at the time, and would have cost too much for the club.

[6] Nevertheless, Jonker experienced his breakthrough at the club, and after two seasons in The Hague, he signed with AZ '67 in 1980 at the age of 29.

[9] Jonker played 19 matches in the European Cup on behalf of AZ '67, and was part of the successful team which convincingly won the Eredivisie with a goal difference of +71, and reached the final of the UEFA Cup in the 1980–81 season, in which he scored in the return leg.

[10] He gained two caps for the Netherlands national team, in which he played against West Germany and Cyprus.