The Scottish Professional Football League is understood to be looking into allegations that a club official forged a player's signature on a contract that was registered with the league.
The claim came from a former employee who says she is taking the club to an industrial tribunal.
The alleged incident took place last month and, although it is unclear which player is at the centre of the claims, he is not believed to be a first-team player.
However, Kilmarnock players awoke to a back-page story about possible points deductions as they continue their battle to avoid a play-off to stay in the Scottish Premiership.
Johnston said: "I saw it in the paper but that's as much as I know so I can't really comment.
"We have just to make sure we focus on football and put any distractions out the way. It's too big a period with the upcoming games to get distracted and have any excuses.
"There is nothing we can do about, we just have to concentrate on the football side of things.
"We have got a lot of big games coming up and we have to make sure we are 100 per cent focused on what is going to be a hard game against Ross County."
Johnston did not feel the need to make a special effort to reassure his players about the story, or seek assurances from chairman Michael Johnston.
The Rugby Park manager said: "I just quickly said to them 'I don't know anything about it', which is the 100 per cent honest truth.
"I'm sure if there was anything, the chairman would have spoken to me earlier, but I've not heard anything."
The Kilmarnock chairman and the SPFL have made no comment on the issue and Scottish Football Association chief executive Stewart Regan is retaining a watching brief.
Regan said: "It is a matter for the SPFL to deal with and we know that is being pursued by Neil Doncaster and his colleagues. We will retain a watching brief, see how the matter unfolds and then decide if and when we need to get involved."
Killie find themselves playing the second-bottom team for the second week running. Partick Thistle sent County into the unwanted position last weekend when they won 2-1 at Rugby Park.
The Jags looked determined to get out of that place but Johnston does not feel an extra burden playing against the current 11th-placed incumbents.
"I don't think there is any motivation needed when you're at this stage of the season and the position we are in as well.
"We know what we need to get out of this situation and it's all about us getting the performance and the result.
"It's a great opportunity but every game is going to be massive between now and the end of the season, not just this next one.
"But we are fully focused on this game, as I said, no distractions, let's go and get a result."