Valero had only been back at Anfield for a year, returning last summer for a second spell after originally working under Rafael Benitez between 2007 and 2010.
In between he built a lengthy coaching career that took him to Inter Milan, Chelsea, Napoli, Real Madrid and a seven-year stint at West Ham before Liverpool brought him back to replace Fabian Otte, who had himself only lasted a year after replacing long-serving coach John Achterberg.
According to The Athletic's James Pearce, Valero informed the club before the end of last season that he wanted to return to Spain, and the exit has been described as amicable and unconnected to Arne Slot's sacking earlier this year.
Colin Stewart, Liverpool's goalkeeper development and pathway lead, will take on first-team duties on an interim basis while the club works through what it calls "a number of candidates" for the permanent role. Stewart himself only joined Liverpool last year following nine seasons at Rangers.
The timing adds another moving part to Andoni Iraola's first pre-season in charge. The new head coach brought four members of his Bournemouth staff with him — Tommy Elphick and Shaun Cooper as first-team coaches, Pablo de la Torre as assistant coach and Tom Webber as tactical analyst — but no goalkeeping specialist, and a further raid on his old club isn't expected given Bournemouth's own coaches, Gareth Stewart and Neil Moss, are considered unlikely to move.
Those arrivals helped fill gaps left by several members of Slot's old backroom staff who departed in late May, though individual development lead Luiz Fernando Iubel remains in place, still linking the senior squad with the academy.
Liverpool's senior goalkeeping options currently include Alisson Becker, who will miss the start of pre-season after a break following Brazil's World Cup exit, along with Giorgi Mamardashvili, Freddie Woodman and Armin Pecsi.