Al-Nassr coach Luis Castro has left the club, the Saudi Pro League side said on Tuesday.
Cristiano Ronaldo's Al-Nassr sit seventh in the standings with five points, having won one of their three opening league fixtures in the campaign.
They lost the Saudi Super Cup final 4-1 against champions Al-Hilal earlier in August.
"Everyone at AlNassr would like to thank Luis and his staff for their dedicated work during the past 14 months," the club said on social media platform X.
Castro, 63, was appointed in July 2023 after more than a year in charge of Brazilian Serie A club Botafogo.
The Portuguese coach led Al-Nassr to lift the Arab Club Champions Cup last year, a competition contested by 37 teams from Asia and Africa.
They finished second in the league last season, 14 points behind Al-Hilal.
He previously coached teams including Shakhtar Donetsk, with whom he won the Ukrainian Premier League in 2019-20, as well as Brazil's Vitoria Guimaraes and Portuguese Primeira Liga sides Porto and Rio Ave.