The newly promoted club has spent a lot of money this transfer window, signing the likes of Rodrigo and Diego Llorente.
But they are hoping to add more, and Cantwell is a deal they can get done by the October 16th deadline.
"We analyse all the players," Leeds sporting director Victor Orta told Yorkshire Evening Post.
"We know them really well, their clubs were our rivals, we analysed [Cantwell] in the Premier League. But it's like a lot of players we've analysed.
"They are players we analysed, we have information and then we need to think about the possibility."