Vitor Pereira said he was taken by "complete surprise and without any warning" after confirming Wednesday he had been let go as head coach of Nottingham Forest with immediate effect.
Pereira signed an 18-month contract at the City Ground in February. He guided Forest to Premier League survival and the semifinals of the Europa League.
There was a break clause in his contract for June, and it is understood Forest informed the Portuguese boss they wanted to go in a different direction.
British media reports have suggested Oliver Glasner is poised to take over at the City Ground following his departure from Premier League rivals Crystal Palace at the end of last season.
"Today marks the end of my journey as head coach of Nottingham Forest," said Pereira in a statement. "I want to say a sincere thank you to everyone connected with this incredible football club.
"Although this decision came as a complete surprise to me and without any warning, I fully respect the club's right to make the decisions it believes are best for its future."
The 57-year-old added: "Naturally, I am disappointed and saddened. I truly believed in what we were building together, and I leave with a sense of pride in everything we achieved over the past months.
"Together, we enjoyed a memorable end to the season. We secured the club's Premier League status, reached the semifinals of the Europa League, and created moments that will stay with me forever.
"Most importantly, I saw a group of players grow in confidence, belief and togetherness."
Pereira, who thanked his staff, players and fans for their support, insisted he wished the club every success in the future.
"I leave Nottingham Forest with no bitterness or resentment – only respect, gratitude and wonderful memories."
Forest declined to comment when contacted by Britain's Press Association.
Pereira, who also kept Wolves in the Premier League the season before, won eight of his 20 matches in charge of Forest, with the two-time European champions now set for a fifth successive season in the top flight.
Former Palace boss Glasner was linked with a number of top jobs across European football after he won the FA Cup in the 2024/25 season with the south London side followed by the European Conference League title a year later.