Not unexpected that the A333s will be retired - they're older, not as fuel efficient, are very short-ranged compared to newer A333s, and with just nine of them, it simply doesn't make sense to keep them. AA has no shortage of widebody planes already on the property and on order.
Back when US ordered the A350s, I assumed that they would replace the A333s. US didn't need 22 growth aircraft when it ordered the A350.