When i read chapter 274, the chapter where Fukuda explained to Nozomi why Ashito is a Fullback. Nozomi said "if we're making use of his vision & passing, there's always the option of putting him in the middle".

I always had this notion. Why isn't Trent operating in Midfield? listening to the online Football community, it seems obvious he can't defend, & with his elite passing, Midfield seems the obvious solution...

However, as someone who's never played Football IRL, the knowledge Fukuda dropped blew my mind. To summarize, there is more to being a Midfielder than just being a good passer. You need to be adept at trapping the ball, & since you'll be pressured from all sides, your vision & split-second decision-making needs to be top-notch.

All, or some of these qualities Trent does not possess. Fullback relieves the pressure from being pressed from all sides, & needed to be aware of your surroundings at all times. It frees up players like Trent to focus on how to progress the ball forward, to get in the right positions for his ELITE deliveries in to the final third.

"Fullback are truly Free"

Side note: Trent isn't a terrible defender like how parts of the football community & some pundits make him out to be. He is not the best defender, but certainly not the worst. Unfortunately, his mistakes are just magnified, with the X-factor he brings to games being ignored.