The Gremio striker impressed last season, scoring 17 goals for the Brazilian club.
He has continued his fine form for Brazil at the Olympics, scoring three goals and creating a further two to help his country to the final against Germany.
Liverpool were linked with a move for the forward earlier this month.
And now Brazilian outlet Zero Hora claim the Reds have been joined by Manchester United in the race for his signature.
The report claims Gremio are demanding £39million for the striker this summer.
But the Brazilian club will allow him to leave for £26m next January.