I genuinely had to read the post from NASCAR three times this morning just to begin processing it. My brain was stuck on "oh, is he retiring?" for fully ten minutes.
He'd been unwell the last couple of races, but no-one really thought anything of it...drivers race sick all the time. He won the Truck series race in Dover just a few days ago:
Zanardi, Busch, Miettenen all in the last month, and Marquez and Zarco had terrifying near-misses at Catalunya; it's been a tough period for the motorsport world.