I think there may be a case of "coaches see something the fans don't" going on at center.
Fuller did absolutely terrible in the first two preseason games, yet Carroll kept signing his praises all offseason and after those games. Then he did better in the third, and now in real action he didn't seem to do bad. He also did terrible last time he played in regular season but that was against Donald. So expectations were very low and he definitely didn't seem like a liability today.
And speaking of Donald, the guy who is closest to him is Buckner, who made Pocic look silly. He does that to a lot of people though. So Pocic did stand out on that play, and I'll take your word that he did bad on many others too.
All that said, much like a good pass rush covers up weak corners, good guards will cover up a weak center, and we have two great ones.
So tldr, Fuller may be serviceable this year.
