Sanders' office confirmed he did not campaign for Ossoff.

[LisaM]

50. Seriously?

In the past, she's been on the ground for Democrats much more than Bernie has (examples: she's campaigned for Patty Murray, Jay Inslee, and Mark Schuette to my first-hand knowledge, which Bernie did not), but anyone who supported her has had to listen to, ad nauseum, post mortems on how she blew the race. She's been pushed aside by those people, while Bernie has been venerated (just open up DU at any point, and count the times his name appears in an OP versus hers).

Given that, it wouldn't be too much of a leap to assume that his endorsement or participation would have been considered an asset by the campaign, while Hillary's endorsement would not currently matter or maybe even hurt. If not, that's all fine, but some people seem to want to have it both ways. I simply called his office to ascertain his level of participation, if any.