One of the big missing names from USAs is Michael Norman, the 2022 world champion in the 400m who finished 8th at the 2024 Olympics. He hasn't raced all year and I haven't seen anything about why.
So I reached out to his agent, Emanuel Hudson, who said Norman "had surgery this season for a matter that occurred last season." Hudson said he wasn't authorized to say the kind of surgery. But Norman dealt with a pelvis injury last season so that would be my guess.
Hudson also represents Sha'Carri Richardson and I asked him what her plans were for USAs. She's entered in both the 100 and 200 but has the bye to Worlds in the 100. He said her plans were up in the air and he didn't know if she would run all three rounds or just one.