The Swiss international, 28, arrived at the Spanish club on a permanent deal last week after spending three years at Craven Cottage.
"They told me about the interest from Valencia really late on. I was just completely focused on working with Fulham," Sky Sports News quotes him as saying.
"However, I think that this is a great opportunity for me and that is why I accepted it.
"I really want to play in La Liga and playing for Valencia is a great challenge for me."
Senderos made 15 appearances for Fulham during the current campaign.