The Jets have the edge in this situation and they are not pressed to make any moves. If someone wants to sign Leon it will cost them a 2nd (and if the Jets feel the offer is fair they also have the right to match it). If Leon isn't back next season it is because the Jets decide to let him leave.
He is coming off of major injury/surgery and I just don't think any club is going to be willing to sign him to any type of significant deal. At the end of the day I think Leon will end up signing the tender the Jets extended to him and try to have a big season next year.