He's been floating between a 110-120 wRC+ for a year and half now. That's already pretty close to useless for player like abreu. If it get's any worse, and it likely will get worse next year or the year after, he becomes an active hindrance.
If he goes on an absolute tear the next month or two I'll rethink this, but right now there's no way I give him more than a year + team option.