Barcelona are nearing a deal to sign Liverpool star Coutinho, just months on after failing to snap him up during the summer.
Yet the Catalan giants could still strengthen further despite flying high in La Liga and the Champions League.
And Spanish outlet Diario Gol say Messi wants Barcelona to sign three Manchester United players once their deal for Coutinho goes through.
The players in question are Ander Herrera, Daley Blind and Juan Mata.
All three players’ contracts expire at the end of the season and renewals are yet to be put on the table.
Herrera could sign to provide competition for the likes of Sergio Busquets and Ander Herrera in the middle of the park.
Mata, meanwhile, could rotate with Coutinho and possibly replace Barcelona captain Andres Iniesta, who is weighing up his Nou Camp future.
Blind, however, is the signing Barcelona arguably need the most.
Messi supposedly thinks the Holland international would be the ideal replacement for Javier Mascherano.
Mascherano could leave the Nou Camp for the Chinese Super League this month.
And Blind, who is capable of playing in defence and midfield, could fill the void left by his departure.
Diario Gol claim Messi also admires Mesut Ozil and Leon Goretzka.
But both players could end up going elsewhere.
Express Sport understands Ozil is wanted as a replacement for Henrikh Mkhitaryan at United.
Goretzka, meanwhile, is likely to join Bayern Munich.