Messi, 26, faces up to two months on the sidelines after tearing his hamstring in Barcelona's 4-1 win over Real Betis on Sunday.
Alves believes Neymar, who joined the Catalan club from Santos in the off-season, is capable of stepping up in Messi's absence.
Neymar has scored four goals since joining Barca, while Messi had netted eight in 11 league matches before his injury.
"Neymar is always ready," Alves told Globoesporte.
"He knows how important he is for Barca and that he was bought just in case something like this happened.
"With Messi out injured, someone has to take over his role and Neymar is ready to do that.
"For the player he is and for the quality he has, he's the right man for the job and I am sure that he will respond positively."
‘I don’t think Liverpool would look at Ollie Watkins, a striker isn’t a pressing issue for them – it’s Arsenal who need one’ Former Reds star explains why his old club don’t need an out-and-out forward this summer
‘He’ll still be playing at 40 at a good level because he’s in such good shape and looks after himself so well. He does everything to be a top professional’: Ex-Liverpool coach insists Mohamed Salah has plenty more miles in the tank
