The pair worked together at Liverpool.
“I know from working with Luis he used to occupy a defence on his own so if you put Neymar and Messi into that it is a very difficult task," said Rodgers.
“In this moment in time Luis is the best striker in the world there is no question about that.
“First of all you have to speak about the man, he is one of the most beautiful men you can come across, he's very humble guy, super professional, a family man who gives everything for his life as a footballer.
“I had the pleasure of working with Luis for two years. He is the best in the world, the biggest compliment you can pay him is he came to an already world class team and made them better. Barca now wouldn't be the same team without Luis in the side.
“We remain in contact, he is an incredible player but an even better person."