According to state law, if a candidate:
(E) Is declared ineligible or disqualified by a court or disqualified by the political party executive committee under ยง 2-5-204;leaving no candidates for nomination or office, additional candidates may qualify for the election or that nomination by filing their petitions as provided by law no later than twelve o'clock (12:00) noon, prevailing time on the fortieth day before the election. If any of these events occur within ten (10) days of the fortieth day, the qualifying deadline shall be twelve o'clock (12:00) noon, prevailing time on the tenth day following the death or withdrawal.
Don't know what the Knox County Charter says (can't find a copy online - anyone?) so it may be different. But this looks to me like it says there is still time (until June 23) for someone, such as a write-in candidate, to qualify to be placed on the official ballot to replace a candidate declared ineligible because of term limits.
I am not a lawyer, and I may be interpreting it wrong, but it seems like a write-in candidate wishing to get on the official ballot could fill out a petition and get 25 signatures, turn it in, then ask for a court ruling under this provision if their petition is denied.
It's too late for the May 2nd primary (and I wonder why nobody mentioned this in the ten days following the Tennessee Supreme Court ruling in Shelby Co.?), but it would seem to apply to the August election.
Maybe a lawyer or election law expert out there could explain all this for us? Paging Herb Moncier...