Tiberius's Exile

Tiberius began to ask his stepfather for permission to return to rome, a request augustus refused to even consider. But we all know now that it was not tiberius's destiny to die in obscurity. So how did he get from exile back into the centre of roman power? Augustus clearly wanted nothing more to do with him, and with gaius and lucius progressing nicely, it would take quite a chain of events for the princeps to accept tiberius back into his good graces.