He has to figure that there's a huge chance he's going up next week. His 'deal' that if Kevin/Natalie won they'd put up Jordan and Michelle was just so he could 'maybe' help himself.

He only has 2.5 chances at surviving next week:

1) Jordan wins HOH (least likely but she was competing well until this weeks POV)
2) He's nominated and wins POV (most likely)
2.5) Kevin wins HOH and keeps his word (50/50 chance) And I think the only reason it could happen is if Kevin wants Jeff's vote in the end, he has nothing to lose by putting Jordan and Michelle up, plus he can slander Jeff to Jordan once she's on the block like 'you're up cuz Jeff made a deal to put you up instead of him', with him taking Kevin off the block, it makes it real. So if Jordan leaves, she's pissed at Jeff (maybe losing her vote in jury), then the whole house will want Jeff gone after that (if he's evicted, he'll vote for kevin cuz he kept his word). If Natalie wins HOH (unlikely) Jeff is on the block guranteed.

If Jordan pulls her weight in this weeks HOH comp and wins, Jeff will win this competition...and i'm thinking Kevin is a close 2nd choice if for some reason Jeff gets evicted.

____________