Jason Garrett was here for a decade though....Still a 'Jerry guy", but Jerry certainly isn't opposed to the young guy either. Kellen Moore seemed to be on that path too until McCarthy ran him out of town. Al Harris has been here a few years now so I wouldn't rule him out as being a possible guy Jerry has taken an interest in, and the Asst HC tag is a bit of a trial run for the post McCarthy era. Jerry sits in those Monday coaching meetings regularly so you know he's familiar with the guy by now.
If you have to go with an interim tag on a HC mid way through this season I think Harris makes a ton of sense. At that point you're going to be down in the standings. Either you get a young guy the team rallies around for the story of the year, or Harris isn't ready for that role and the team ends the season with a top 10 draft pick. I just don't see the point in an interim HC like Zimmer fighting to get this team to 8 wins in what would most likely be a lost season at that point.