Celtic threw away a two-goal lead in Dingwall to suffer their second consecutive Clydesdale Bank Premier League defeat after Steffen Wohlfarth headed an injury-time winner.
Lennon, who made five changes following the 2-0 defeat by Juventus, most of them enforced, said: "These players owe me. I have pulled them out of places that no-one had heard of and put them in the shop window. And I want payback now. That is simply not good enough."
He went on: "If they want to go they only have to knock on my door and say 'I want to go' then I will leave them out and play someone else who wants to be here."
Celtic are 15 points ahead in the SPL but Lennon had urged his team to wrap up the title as soon as possible.
"It has become a problem because we have lost the last two away games to really poor performances in some aspects of the game," he said.
"I'm not happy with the attitude of some of the players. Some of them look like their minds are elsewhere at other clubs. I don't know if they have been tapped up, I don't know where they are mentally, but you can tell by their body language they are not with us at the minute and I'll have to sort that out."
Manager Derek Adams felt County were well worth their win.
He said: "Celtic hadn't really done anything and we were 2-0 down. They were two poor goals from our point of view, crosses into the box and Michael (Fraser) knows he should have done better with both goals.
"We knew we had the quality in the side to go on and do something in the game. We got ourselves back in it and thoroughly deserved to win the match."