Zalazar joined the youth categories of Albacete Balompié in 2007, aged eight.[4] In 2014, he moved to Málaga CF and was initially assigned to the Cadete squad.[5]
In 2018, after finishing his formation, Zalazar was promoted to Málaga's reserve team in Segunda División B, but remained unregistered for the entire season after the club had no free registration spots;[6] he then refused a loan to a Tercera División side, as his contract was due to expire in the following summer.[7]
Three days after joining Eintracht Frankfurt, Ekstraklasa side Korona Kielce signed Zalazar on a one-year loan deal for 2019–20 season.[9] He made his professional debut on 20 July 2019, coming on as a 70th minute substitute for Erik Pačinda in a 1–0 league win against Raków Częstochowa.[10]
Rarely used in the first team, Zalazar also played for Korona Kielce II in the III liga, scoring three goals in 10 appearances.
Loan to FC St. Pauli
On 6 August 2020, 2. Bundesliga club FC St. Pauli announced the signing of Zalazar on a season-long loan deal.[11][12] He scored his first professional goal on 19 October, netting the equalizer through a penalty in a 2–2 home draw against 1. FC Nürnberg.[13]
Zalazar finished the 2020–21 season with six goals in 35 appearances overall, as St. Pauli finished in the 10th position.
Schalke 04
On 4 August 2021, Zalazar agreed to join fellow second division side Schalke 04 on a season-long loan with an option to make the move permanent until 2026.[14] On 25 March 2022, Schalke exercised this option, and he agreed to a permanent four-year contract with the club, effective as of 1 July.[15] He ended the campaign as a starter as the club achieved promotion to the Bundesliga as champions.
Zalazar made his debut in the main category of German football on 7 August 2022, starting in a 3–1 away loss against 1. FC Köln. He scored his first goal in the top tier six days later, netting the opener in a 2–2 home draw against Borussia Mönchengladbach.
Born in Spain to Uruguayan parents, Zalazar was eligible to represent both Uruguay and Spain at international level. While his older brother chose Spain, he followed his father's footsteps and chose to play for Uruguay.[17]
In June 2023, Zalazar received his first call-up to the senior team for friendly matches against Nicaragua and Cuba.[21] He made his debut on 14 June, scoring two goals in a 4–1 win against the former.[22]
^"Sub-20 Plantel para Chile 2019" [Squad of the under-20s for Chile 2019] (in Spanish). AUF. 19 December 2018. Archived from the original on 16 January 2019. Retrieved 15 January 2019.