Hendrie was asked to pick a particular player who had stood out for him for the Whites this season and selected the Spaniard.
He added that there is still room for the former Huesca ace to improve, but overall is impressed with the attacker.
Hendrie said: "It obviously has to be Samuel Saiz. He’s a terrific little player and a really good find.
"He’s been excellent, my only criticism could be that he sometimes tries the fancy finish instead of being clinical, but he has been the star man for me."
Saiz, 26, has scored four goals and provided three assists in 14 appearances for Leeds this season, and has shone despite the club's poor form.
The attacking midfielder should get even better as he further adapts to English football, although needs others around him to raise their game too.
Hendrie played for Leeds in the 1989/90 season, before signing with Middlesbrough, who the Whites face this weekend.
Leeds are 10th in the league while opponents 'Boro are fifth, with three points separating the two teams.