Apparently her coach decided it wasn't worth it to try to rush back and get in a time standard for this year's USAs. It actually seemed like they were recording this during USAs a couple weeks ago, so hopefully this month if its on the early end?
[i] Editor's note: It drives us nuts when people reference other people's work but don't provide a link. Episode 5 below:
Editor's Add #2: Here is a recap of what she said on the podcast: http://www.letsrun.com/news/2018/07/mature-mary-cain-prepares-return-track-racing-2-years-away-5-takeaways-cains-recent-podcast-appearance/