Rey Mysterio has been in negotiations with both WWE and Global Force Wrestling.
Justin Barrasso of Sports Illustrated reports that ever since the 4th season of Lucha Underground has been up in the air, Mysterio has reached out to both WWE and GFW about possibly working for them. While GFW would offer Mysterio a lighter work scheduled, he could still very well end up returning to WWE to make big money.
Mysterio is currently signed through the end of the third season of Lucha Underground, which is set to air in September. He would then be free to work for any company after his 90-day non-compete clause expires.