There's certainly hope for it but nothing has actually been said about it. Cote's said in the past (I believe) that she's open for guest appearances & she & Michael are still friends so many this will be the opening needed to bring her back for an episode. Maybe they'll end up leaving together & that's how Tony'll leave I'm not going to get my hopes up too high that she'll make an appearance but it would be nice if it happened either before he leaves or in his final episode