The 22-year-old midfielder has become one of the most sought-after talents in world football on the back of his displays for club and country.
A star showing for Germany at the 2017 Confederations Cup helped to further enhance his profile, while he has four goals in 10 appearances for Schalke this season.
Barca are reported to be among those closely monitoring his progress, alongside other heavyweight outfits such as Bayern Munich and Manchester United, and Ter Stegen believes his international colleague has the ability to join the global elite.
He told Revier Sport: “Leon is a fantastic player. I like him as a footballer and as a man.
“He has outstanding footballing qualities. I have to say that he could play for one of the top European clubs.”
Pressed on whether such a switch could see Goretzka join him at Camp Nou, Ter Stegen added: “What I have seen of him in the national team is extraordinary and remarkable. I also think he will get better in the future.
“I don’t know who will get him in the end - maybe he stays with Schalke 04 and then you can only congratulate that club.”
Goretzka could be on the move in 2018, as his current contract continues to run down.
Schalke have been unable to tie him to fresh terms and they may be forced to cash in when the transfer window re-opens in January.
If they opt against sanctioning a sale, then he will become a free agent next summer.
Whatever decision is taken, there is expected to be a fierce scramble for his signature.
Many of the interested parties will likely want a deal done before the World Cup finals in Russia, as another standout showing in front of a global audience will bring even more clubs to the table.