Truly, Marriotta is another of those highly athletic QBs that makes his highlight reel plays using his legs.
And typically, these guys have a very good 1st and 2nd year, and then either flatten out quickly or decline because teams figure them out and because they begin to get injured.
There are exceptions of course. But in his 3rd year in the league, and in game 9 when he has more INTs than TDs (and not very many TDs to start with), that's not a good sign. Especially when you do have a good OL and decent skill players. If a QB is progressing, his completion % ought to go up, and his TD to INT ratio should improve.....not the other way around.
The Steelers game put his deficiencies on display. Inconsistent arm, hangs onto the ball too long, barely average accuracy. His INTs were not the result of great Defensive plays; just bad decisions and poor accuracy.
The problem for Marriotta is going to be that he is not physically going to be able to take the pounding if he continues to use his legs to make his best plays. Take that away and you have a journeyman QB (just like the Panthers figured out with Cam). I think the hits are already taking a toll. And while he is a pretty good passer, he's not upper echalon. So I think over his career he's likely going to be a decent starter, with a few good moments, but nothing special. He'll be a guy that in another couple of years they'll be looking to replace if they can find someone better; but......then it'll be time to pay him that second contract and you know he'll want huge dollars based on very average stats and wins. But will he be anywhere near good enough to warrant it? And can the Titans find that someone who is better? Not easy. Drafting an "OK" QB high can prove to be very problematic. Better that they are an outright bust or a huge success.....nothing in between. It's easy to move on from an outright bust, and its also easy to pony up the big bucks to a huge success. But a middle of the road guy? That's tough because even finding a middle of the road QB to start for you isn't easy these days.