Diaz completed a £37m move from FC Porto in the January transfer window, adding more firepower to an attacking frontline that has the likes of Sadio Mane, Mohamed Salah, Diogo Jota and Roberto Firmino.
Diaz comes with a huge reputation, having scored 14 goals in 18 Portuguese top flight games this season, but Klopp expects him to take some time to adapt to the demands of the English game.
"Luis, let me say it like this, if he now came and stepped on the pitch and was immediately at his best and playing better than everyone else it would be really strange," Klopp said ahead of Liverpool's FA Cup fourth-round tie with Cardiff City.
"He needs time to adapt, but that doesn't mean I speak about four or five months, I haven't even seen him yet in training so maybe we should wait a little bit.
"But I'm really happy and excited about the signing, it's a really good sign that we work on all fronts to improve this team, that's how it always is in football. Obviously how it works is we have to be successful now and in the future. He can help with both that's a really good thing.
"We signed him because we like pretty much everything about him. I followed him now for a while not only since we played them twice in the Champions League.
"He has the speed, skillset, and character to have a really good career. We want him to have that career with us.
"I'm really happy we could get him in now, he can help us, we can help him. His story so far is a special one. Now he's one of us, we can't wait to welcome him here."
