If he really doesn't run he must be hurt or trying to take of his health in some way.
It's still a big deal to take a shot at being US champion.
It mean more to his branding and resume than anything else he is likely to accomplish this year.
When you talk about Manzano you mention things like, top 3 at USATF 8 years in a row.
I will note that a healthy Wheating did not run this event in 2010.
He was coming off of an NCAA double, skipped USATF and ran a 3:51 mile at Pre before heading to Europe and running his 3:30.90.
He still does not have a USATF title to his name.