The Spain Under-21 star is sad to see his former team-mate leave Camp Nou but is excited about the potential of youngster Sergi Roberto
The duo came through the ranks at Camp Nou together and while the full-back is disappointed to see the playmaker depart, he is excited by the potential of Sergi Roberto, who is set to take his place in the squad.
"He'll become one of the best in the world," Montoya told Marca.
"That's the path he's chosen. Sergi Roberto is coming up right behind him and we hope he can be just as successful as Thiago."
Camp Nou youngsters Gerard Deulofeu and Rafinha have both been sent out on loan for the 2013-14 season and Montoya believes they will both benefit from their respective spells away.
"It's really tough to break into the team because we have the best players in the world here. We youngsters have to be patient or go out on loan to get some minutes and keep up our fitness."
Barca's arch rivals Real Madrid have strengthened their squad with the likes of Isco and Asier Illarramendi this summer and Montoya believes they will be a force to be reckoned with next term.
"Real Madrid have made some very good signings. It's good news because it means Spain's youth set-up is doing its job."