Sem Westerveld

Westerveld made his professional debut with Jong AZ in a 1–0 Eerste Divisie loss to Roda on 4 January 2021. On 18 June 2021, he signed his first professional contract with AZ for three years. He suffered a torn cruciate knee ligament in 2024 and spent a year out of action. He returned to the Jong AZ team for a match against Vitesse in April 2025, in a 2–2 draw. On 2 July 2025, Westerveld joined Eerste Divisie club MVV on a one-season loan. He quickly established himself as a key figure for MVV, producing a series of decisive performances that included a penalty save in a goalless draw away to Jong Ajax. Having struggled with injuries for much of the previous two and a half years, he described the run of form as a personal breakthrough after a "long, dark period". On 6 July 2026, Westerveld returned to his birth nation and signed a three-year contract with Real Zaragoza in Primera Federación.

As of match played 25 April 2026

Westerveld was born in Spain to a Dutch family, as his father was playing football in the country at the time. His father Sander Westerveld and grandfather Hennie Ardesch were also professional football goalkeepers. Sem was born in San Sebastián, Spain while his father was playing for Real Sociedad. Sem holds dual Spanish and Dutch citizenship and is a fluent Spanish speaker.