Notre Dame coach Brian Kelly shows his unhappiness with sophomore Jerry Tillery over Tillery's actions toward USC players, including stepping on the foot of one and appearing to nudge the head of another. (1:07)

Notre Dame defensive lineman Jerry Tillery apologized Monday for his actions in Saturday's loss at USC, in which the sophomore appeared to nudge one injured Trojans player in the head and step on the foot of another during a fourth-quarter drive.

Tillery nudged the helmet of USC running back Aca'Cedric Ware with his cleat while Ware was down after a hit by Irish safety Nicco Fertitta, who was ejected for targeting. Tillery's move went unnoticed by officials in the Irish's 45-27 loss.

Tillery was later flagged for an unsportsmanlike conduct penalty after he stepped on the exposed foot of Zach Banner while the Trojans offensive tackle was on the ground.

"I want to take full responsibility for my actions on Saturday," Tillery said in a statement posted to his Twitter account. "I am truly sorry. I acted in a way that was out of character for me. What I displayed in those two instances were completely unbecoming and not indicative of the kind of player or person I am. My actions in those instances do not represent what my family or Notre Dame has molded me to be.

"I want to especially apologize to Aca'Cedric, Zach, their families and anyone else affected by what I did. I assure you I will learn and grow from this moment and become a better man because of it."

Ware and Banner took to Twitter to acknowledge and accept Tillery's mea culpa.

Mistakes happen bro, I'm good, Ced's good. You earned my respect from your apology. Take care. https://t.co/9y1L6SqOzi — Zach Banner (@zachbanner73) November 29, 2016

Notre Dame coach Brian Kelly told reporters after the game that he would speak with Tillery.

"I did not [see the plays]," Kelly said. "I know he got a personal foul penalty, and I subsequently took him out of the game. I had a conversation with him. Any time a player has a personal foul penalty, I pull them out and have a conversation with them. I did that with Jerry, but I did not see [the plays].

"Accountability is built within any program. Jerry has to be accountable for his actions every single day. Jerry is a good kid, and if he made a mistake, we'll hold him accountable for that mistake. We'll take a look at it."