Detroit Lions defensive coordinator Kelvin Sheppard had high praise for Terrion Arnold following his first career interception against the Minnesota Vikings—but also issued a stern challenge. While Arnold’s coverage skills have shined, Sheppard made it clear that the young cornerback still has major room to improve in one crucial area: run support.
Speaking to reporters on Thursday, Sheppard was direct about his expectations.
“Terrion’s absolutely made strides — his coverage has been great and his technique at the top of routes is improving,” Sheppard told Lions OnSI. “But when it comes to defending the run, that part of his game just isn’t where it needs to be right now. It’s unacceptable, and he knows that.”
A Lesson From a Mentor
Sheppard credited much of his defensive philosophy to former Lions defensive coordinator Aaron Glenn, who taught him that the foundation of a defense’s toughness often shows through its cornerbacks — especially in stopping the run.
“Aaron Glenn, who’s one of my biggest influences, always told me that your defense’s identity is revealed when your corners have to make plays in the run game,” Sheppard explained. “If you want to call yourself a physical defense, show it when your corners are setting the edge.”
This mindset aligns perfectly with Dan Campbell’s no-nonsense culture in Detroit — a defense built on aggression and effort.
“We don’t want just cover corners,” Sheppard emphasized. “Coverage is only part of it. Our defense stands for being physical, violent, and tough. That has to show up every snap.”
Effort Isn’t the Issue — Technique Is
Despite his criticism, Sheppard defended Arnold’s mindset, noting that his shortcomings come from technique, not effort.
“It’s not that he doesn’t want to do it,” Sheppard clarified. “He’s in position; it’s just about learning to finish. You’ve got to keep your feet moving in this league — you can’t just dive in. That’s how you win those one-on-one battles.”
To illustrate his point, Sheppard referenced veteran linebacker Alex Anzalone, whose consistent fundamentals make him an example for younger players.
“Today’s NFL is full of elite athletes,” Sheppard said. “You can’t just hesitate. You’ve got to attack the point of contact with confidence.”
The Takeaway
Arnold has already shown the talent and instincts to become a lockdown corner in Detroit’s secondary. The next step in his growth, according to Sheppard, is translating that same intensity to the run game. And with Detroit’s coaching staff known for demanding excellence, it’s only a matter of time before Arnold’s “unacceptable” run defense becomes another strength in his arsenal.
