More than fine? Lol He may not get sub'd but he'll be working his arse off not to. This isn't fricking Diego Sanchez or Erik Silva he's fighting. Maia is not just one of the top BJJ fighters in MMA, he's one of the top BJJ players in the world at any weight.
Maia had a submission win in his last fight... but before that he hadn't submitted anybody in nearly 4 years. Before his last fight, his last submission win was in February of 2009 at UFC 95 against Chael Sonnen.
That's 9 fights.
Demian Maia is great at BJJ, but plenty of people have avoided his submission attempts.
Fitch could certainly lose, and if he does it will be by submission. But it is highly unlikely that Fitch will get caught in a sub.
1. Because he is a wrestler with excellent control and submission defense
2. Because he knows he's fighting Demian Maia and he will be extra aware and extra careful