Taylor Anderson writing for The Bulletin:

These Republicans are seeking re-election: Sens. Herman Baertschiger Jr, of Grants Pass; Brian Boquist, of Dallas; Ted Ferrioli, of John Day; Fred Girod, of Stayton; Bill Hansell, of Athena; Tim Knopp, of Bend; and Jeff Kruse, of Roseburg.

Almost every Oregon Senator is running for re-election.

The fate of Sen. Doug Whitsett, R-Klamath Falls,wasn’t immediately clear. His term expires at the end of next year but his name was left off the list of Republican senators seeking re-election.

Whitsett likely didn't want to be pressured by the caucus. I wouldn't be surprised if he announces his re-election himself later this year except on his own schedule.