Rayo part company with coach Sandoval
"The club have decided not to renew Sandoval's deal," sporting director Felipe Minambres told a news conference. "We consider it a very difficult decision but it is the best one for the club."
Sandoval became a cult figure with fans as he led the Madrid-based club, who are in administration, back into La Liga after an eight-year absence last year but he fell out with the club hierarchy towards the end of the season.
Rayo's positive attacking play won over many neutral supporters and they were pushing for the European places before a dreadful last two months of the campaign saw them plummet down the table.
They were saved from relegation by a 90th-minute winner against Granada on the final day of the season.