While Polsky is leaving the show we do have some good news on who is apparently returning. Mike Fox of the Fox brothers who wrote The Gift of Maud Pie, Applejack's Day Off and P.P.O.V. left this little teaser up on Twitter in response to a fan.
It's not outright confirmation as the staff usually likes to play around with us, but from the looks of it we can expect Mike and hopefully his brother to return for season 7!
Thanks to Dominick for sending it in and MegaSean45 for asking the question.
Update: Confirmation that both of the brothers are indeed coming back!