Gerrard, 27, said: "From what I've seen of him so far on the training pitch he's got everything you need in a Liverpool player.
"He has a good touch, good passing and he's also a good lad off the field.
"He's only young but I've no doubt that he's got a bright future at the club and it's good to have him onboard.
"He's captain of the Brazil Under-20 team and so obviously has ability.
"I expect him to be knocking on the door of the first team before too long and hopefully, in time, he can help us win many trophies."