After all the hype and the excitement and how much of a Muppet fan he is...I just don't see why he would not be involved. I mean almost every interview I see of him...he mentions something about puppets or the Muppets.
The toughpigs article quote has a very good reason...
TIME
it was nothing short of miraculous that he even had time to write and star in this movie when he's in like everything, especially a highly popular weekly television sitcom. I'm sure he also has at least one other project he'd work on as well. So if he can add some notes to the project, that's fine... if he manages to find time to get a pass of the script in that's also good... but if he can't, he can't.
But the confirmation alone is pretty good news. I mean, sure... now you get news that a sequel is happening a week after the movie comes out at the
latest. There was no doubt Disney would have another Muppet film in the wings somehow. It was very much a low budget film, an no matter how it did, it wasn't a huge loss of money if no one saw it (unlike G-Force)... and it managed to almost double it's budget domestically.
That said, I really hope this isn't a direct sequel, but rather a follow up with another type of movie, like the Muppets usually have.