The New England Patriots are preparing for a Week 4 matchup against the Carolina Panthers on Sunday, and head coach Mike Vrabel has warned his team about its opponent’s “dirty” strategy.

During his media availability ahead of Sunday’s game, Vrabel discussed the knuckle-ball kickoff strategy employed by kicker Ryan Fitzgerald and the Carolina Panthers special teams unit. When describing the challenges faced when playing against this strategy, the Patriots’ sideline leader referred to it as a “dirty kick.”

The Panthers’ opponents have the worst starting field position in the league through the first three weeks of the season, starting at their own 21-yard line on average.

“It’s impressive. I sat there and looked at for two hours last night,” Vrabel said earlier this week. “I mean, impressive. They’ve got good players, they’ve got great speed, they change the scheme up on you… That will be critical that we’ll be able to protect the guy with the ball.”

“It starts with the kicker,” Vrabel continued. “He kicks a good kick – dirty kick. He’s had the returner sometimes confused. When he kicks them deep, they’re right at the goal line forcing you to return them… We’ll have to be prepared for that.”

Fitzgerald openly discussed his strategy earlier this week.

“We want it to be hard to track in the air and hard to catch whenever it hits the ground,” the Panthers’ kicker said, via team insider Joe Person.

Vrabel and the Patriots off to a 1-2 start, suffering losses to the Las Vegas Raiders and Pittsburgh Steelers. Led by some strong play from second-year quarterback Drake Maye, New England logged its lone victory of the year with a 33-27 final score over the Miami Dolphins in Week 2.

The Panthers are also 1-2 to begin the year, but have some positive momentum following a 30-0 win over the division rival Atlanta Falcons in Week 3.

Sunday’s Week 4 matchup will kickoff at 1 p.m. ET.