I had to look it up on YouTube. I didn't see Fuller on the 3rd and 22 or the 3rd and 25. Maybe that was the game he got hurt in? Or maybe it was the Giants game he got hurt in. I really can't recall the blown coverages are all blurring together.
Nevertheless, the Rams have been allowing chunk plays over the middle all season no matter who's on the field. It appears that they are deliberately leaving the middle of the field open and it was that way on both the 3rd and 23 and the 3rd and 25 (it felt terrible just having to write that).