It'll be interesting to see how this plays out since the Games are the week after USAs. Presumably USATF will have to select the team well before USAs. Then if someone surprises at USAs, will they beg off?
http://www.usatf.org/usatf/files/e3/e3ec9427-2caf-4381-81f0-b8e82fe703c9.pdf