Naismith, along with former Manchester United striker Danny Webber, ex-Stanley loanee Piero Mingoia, and midfielder Josh Windass are all looking to earn contracts at the Store First Stadium.
But the Scotland youth international, 21, was singled out for special praise from Beattie following Saturday's 1-1 draw against Tranmere.
"I think there's a very talented footballer in Kal," he told the Lancashire Telegraph. "His confidence needs boosting and I think he thrives on responsibility.
"I said to him before I want to see you go out there and enjoy playing football because you're a good player, I want to see you smiling and as you've seen he is a totally different player, he's a special player."
Beattie added: "The application of the players I don't think will ever be in question, we're just getting them to express themselves. They are growing in confidence as a group and I'm very pleased."