Arsenal have made contact with Borussia Dortmund to understand if they are ready to sell defender Neven Subotic, transfer market expert Emanuele Giulianelli revealed on Twitter.
The 27-year-old is also a target for Cologne.
Last week, the Serbian made it clear that he wants to leave the club after struggling to secure regular first team football last season.
"Football is an important building block of my life which I love and don't want to be without," he said.
"I am at the best footballing age right now and want to use that time to further myself and my club, and to have the feeling to be needed on the pitch, and be able to give it my all for the club.
"That's what I am thinking about right now.
"I don't want to earn my money on the bench, but rather want to be an active part of a story, as was the case until last year.
"I hope you can relate to it and understand it. BVB is in my heart, and will always remain there."