Not a rookie, but I read Grayson Murphy's name come up positively from several different writers, though it was apparently against players near the bottom of the roster. That's peaked my interest, because he was productive in college, despite subpar length and measurables.
Another non-rookie, Isaiah Johnson, appears to have had a nice start too.
By most accounts, the defense has looked strong up front, despite Sielernot really participating.
At the end of the day, none of this matters until the real physical activity starts.