The 23-year-old attacker played a key role in the Eagles' domestic treble last season but will spent the 2014-15 campaign at Mestalla.
The Real Madrid youth academy product joined the Eagles in 2010 and played a key role in last season's domestic treble success.
However, Valencia has confirmed that the 23-year-old attacker is now set to seal a return to Spain.
"Once the contractual documentation has been completed, the player will undergo a medical at 21:30pm [on Wednesday] at the Ciudad Deportiva in Paterna," a statement on Los Che's official website read.
"He will then hold a press conference at the media center of the facility, alongside president Amadeo Salvo and general sporting manager Francisco Joaquin Rufete."
Rodrigo, who has represented Spain at Under-23 level, netted 18 times in 40 appearances in all competitions for Benfica last term.