I've been wondering this for awhile. Steve Perry won't perform with Journey anymore. But Gregg Rolie has been out of Journey longer than Steve has. Is it possible he might do a duet with him? I've been waiting for some interviewer to ask him this.
Never ever ever will happen (IMO). While Steve is grateful for the time he had with Gregg, Gregg is FULL of sour grapes for Steve. And Steve's is not going backward but forward with his own stuff. Gregg probably would drink poison than do anything music wise with Steve.