I will cut Grella some slack about the second half of last season for two reasons: 1) He and his wife brought home a new baby which is very disruptive, and 2) he was playing with a sports hernia and was likely playing with a great deal of discomfort. I'd give Grella another year without a moment of doubt, although it's possible (likely) that if both Veron and Royer show well in preseason then Mike and Muyl should start on the bench, with Grella coming in as a super-sub. Sub-par season or not, I've never seen the guy quit out there.
You can cut Grella slack, but not Marsch for playing him.