The 36-year-old says that he will convince the Mexico international, who was relegated with Mallorca in 2012-13, to join the newly promoted Liga side this summer
The ex-Tottenham attacking midfielder, who was relegated with Mallorca in 2012-13, is reportedly seeking a move away from the Islanders during the summer in a bid to boost his chances of being selected for Mexico's World Cup campaign.
Valencia, as well as MLS outfit LA Galaxy, are also monitoring the former Barcelona starlet, but ex-international team-mate Franco says that he will try to persuade the 24-year-old to join newly promoted Villarreal.
He told Marca: "I have not spoken with him but I have spent lots of time with him in the Mexico team and I can say he is a great player.
"Gio is fast, strong and has some great qualities and, if I speak to him, I will try convince him to join Villarreal."
Franco enjoyed a three-year spell with the Yellow Submarine from 2006 until 2009, netting 20 goals in just over 100 appearances.
Dos Santos has a contract with Mallorca until June 2016.