The youngster has already had a trial at Arsenal and Jefferies admits he faces a tough job holding onto his prize asset at the end of the season, with the Old Firm likely to be leading the chase for his signature.
The Killie boss said: "If I'm being honest, I would find it very strange if we didn't get some enquiries from clubs.
"As well as the goal, the way he put himself about for the team was great. He was a handful out there.
"If he had to stay here, it wouldn't be the worse thing in the world for him.
"He enjoys his football here, and he's only 20, so another year would be great.
"I'm going away on holiday in the summer and I'm just not going to put my phone on!
"Sometimes he is the difference between winning games and not and he showed that against Rangers."
Asked whether Naismith is likely to join the list, the Gers boss said: "We are looking for a number of players and we will try to bring a few in.
"Whether Steven Naismith is one of those or not, you are free to speculate."
"We can't argue with the result due to the manner in which we played."
Jefferies was thrilled with the result, saying: "The idea was to get a point so to get three points is so satisfying because we've now clinched fifth place and this is one of the hardest places to do that.
"There were some outstanding performances and they worked hard. 'Naisy' was a constant problem for them. It was a finish fitting to win any game.
"Rangers don't like getting beaten, especially in the last game at home, so it's a wee feather in our cap to come away with the win."