Barcelona chief Ariedo Braida was in Germany on Friday night.
The Italian attended Schalke's clash with Bayer Leverkusen, reports BILD.
Braida confirmed Barca's interest in Goretzka, though insisted it was too soon to consider whether a bid would be made. The youngster's S04 deal expires in June.
"He is certainly a great player, but for Barcelona it is too soon," said Braida.
"I travel around the world in search of great talent, but our demands are extremely high."