Took 7 months for me to ask??

[jjrye22]

Here is a good example of needing to get the description as exact as possible.

Originally Posted by TrojanHorse

During a game, our OL doubled the DT. In the process of this, one of our lineman slips and unintentionally hit the already engaged DT in the knee area.

Originally Posted by TrojanHorse

the player was going to drive the DT up the field, he lost his footing and blocked below the waist.

In your first quote you say they were involved in a double team and the lineman slipped low.
In your second quote you say the lineman was going to block and slipped low.

(Note: I only know NCAA - FED might be different).
There is an important distinction here, since the rule says the INITIAL contact needs to be below the waist.
If the lineman was involved in blocking high, and slipped low, I would say no penalty - but one might come out if the official only saw that later part of the action.
If the lineman was trying to block and slipped and made the first contact low, I have a penalty. Intent is not part of the rule, only the contact.