The actor best known for playing Robin Colcord on Cheers died last week. I found out from today's blog that he guest starred on The Middle. What was his role there and what episodes?

http://blog.sitcomsonline.com/2015/07/metv-network-fall-2015-schedule.html

He played a grumpy teacher who gave Sue Heck a hard time in the season 4 episode "The Smile".