The 25-year-old penned a long-term deal with the Reds on Sunday after Liverpool agreed a reported £7m deal for the uncapped Spaniard.
Rush, who scored 346 goals for the Merseyside outfit, admitted he is pleased to see Brendan Rodgers move swiftly in the summer transfer market.
“It’s a very exciting addition to the squad,” Rush told Liverpool’s website.
“He comes from Spain so he’ll know what to expect. It will be different playing in the Premier League but the football Liverpool play will most probably suit him.
“We like to pass the ball around and hopefully he will take the chances. He will be given chances and let’s hope he can take them because he does look a fine prospect.
“He has a proven record in Spain and I just believe the football Liverpool play, and they try to play total football, will suit him.
“We have had some great players come to Liverpool from Spain and hopefully he will be another one.
“I think it’s important to try and do the business early to give Brendan the chance to work with the team in pre-season.
“Sometimes if you get someone at the end of the pre-season it’s harder for the manager, so if you can get the business done early and Brendan can work with them early that will be better for team spirit as well.”