Spanish manager Julen Lopetegui has left Wolverhampton Wanderers after less than a year in charge following differences of opinion, the Premier League club announced on Tuesday, three days before the start of the new season.

Neither party gave detailed reasons for the Spaniard's departure but British media reports suggest the 56-year-old former Real Madrid and Sevilla coach was unhappy with the lack of investment in the squad.

The club have lost key players such as former captain Ruben Neves to Saudi Professional League side Al-Hilal, Nathan Collins to Brentford, Conor Coady to Leicester City, Raul Jimenez to Fulham and Ryan Giles to Luton Town.

Lopetegui was named as head coach on a three-year deal in November when the West Midlands club were staring at relegation, and he oversaw a turnaround to pull them up to 13th, sealing their top-flight status.

Lopetegui had replaced caretaker manager Steve Davis, who was put in charge of the team following Bruno Lage's dismissal in October.

"While our ambition had been to move into the new season together, it is public knowledge that there were differences of opinion on some key topics and it was agreed by all parties that it would be best to part ways ahead of the new campaign," Wolves said in a statement.

Lopetegui, who represented Barcelona and Madrid during his playing career, began coaching in Spain's youth set-up before spells at Rayo Vallecano in the Spanish second division and Portuguese club Porto.

His most successful stint in club management came at Sevilla, where he spent three years in charge, leading the La Liga outfit to the Europa League title in 2020.

"I wish Wolves and everybody at the club the very best of luck for the future, and thank them for the opportunity granted at the time to take charge of this wonderful club," Lopetegui said in a statement.

Gary O'Neil, who helped Bournemouth to secure their top-flight survival last season, steering them to a 15th-placed finish in the league after taking over from Scott Parker, is reportedly set to replace Lopetegui at Molineux.

The Premier League season begins on Friday and Wolves go to Manchester United for their first game on Monday. (Reuters)