Watching live in real-time, I immediately yelled out loud "there's no way that's a fumble. He never caught the ball."
However, upon reviewing it on the instant replays, it seemed to be a lot closer to being a fumble than not being a fumble to me.
I suppose it was just one of those judgement calls that we sometimes get or sometimes don't get. It absolutely changed the whole momentum of the game, as we all knew it would as soon as it happened. Luckily, it did not end up mattering.
FWIW---I absolutely agree with Belichick's decision NOT to bench Ridley for even one series. As he said (and I pointed out to my wife) sometimes the defender just makes a great play and there's not much you can do. The only time I think it's good to bench the player is if their technique is wrong, and they need to learn a lesson. Sometimes you see those players carrying the ball like a loaf of bread and they end up putting it on the ground. Those are the players that need to be benched and taught a lesson; otherwise, some fumbles are just part of the game and can't be stopped or prevented.
At this point in time, I'm not sure that we're going to be able to "teach" Ridley any more lessons by benching him that he already knows at the moment. If anything, it may even start to contribute to a lack of confidence and/or mess with his head.