The Turkey international has talked up a switch to Arsenal in the last week.
Mustafa Dogru, Soyuncu's agent, declared: "I'm not surprised by the interest. Caglar is a modern defender. He is fast, strong with both feet and is an excellent fit.
"I think the Premier League is ideal for a defender with his attributes."
Freiburg are demanding top price for Soyuncu, with 25 per cent of any sell-on fee due to former club Altinordu.