The midfielder signed a four-year deal with The Che after negotiations over a new contract at Villarreal broke down.
Lopez was the target of stinging criticism from Villarreal president Fernando Roig who insisted the player had presented unreasonable demands to the club in order to engineer himself a move.
However, the 24-year-old chose to ignore the controversial end to his stay at El Estadio Madrigal and instead thanked his former club for the opportunity they had given him.
"Thankfully everything has been resolved because it has been a complicated week," said Lopez.
"I don't want to comment (on Roig), I only have words of gratitude for Villarreal.
"Valencia though have given me the possibility of playing for a club who excite me greatly.
"The competition for places here is good and can only benefit the team."
