ISF / Undershirt of the Pitcher

[mach3]

I had a situation last weekend that I would like to get some oppinions about.

Talking ISF.

The Pitcher has a white Undershirt - I know that this is not a problem. But that undershirt finishes in the hand of the pitcher, touching the ball w/ every pitch.
The rules do not indicate that this is illegal directly, but I am not sure about the intent of the rules.

Rule 6.6
d. The pitcher shall not wear tape on his fingers, or a sweatband, bracelet, or similar type item on the wrist or
forearm of the pitching arm.

In ASA there is a rule prohibiting an undershirt the is too long, right? At least that is what I read out of POE 32. Pitchers Uniform.

Now does ISF also wnat to see a gap between the undershirt and the ball? Or was ist legal, what the pitcher did? If it was not legal, was it an illegal pitch?

Thanks for your help

Raoul