At one point, it seemed that he was indeed going to be traded, but talks have shifted a little bit and an extension with Philadelphia is not off the radar anymore.
If the contract negociation doesn't go the way the Flyers want, well, Ristolainen is indeed going to play for a new team soon. Let's not forget that some reports indicated Chuck Fletcher made an offer north of 6M$ per year, but it has been denied a short time ago.