Trying to Figure Out Sieler's Slide

One of the biggest surprises for the 2025 Miami Dolphins is the play of interior defensive lineman Zach Sieler. 

The veteran received a contract extension this summer and has been one of the team’s top players for the past few years. If anyone on this team wouldn’t be subject to the general poor play that has plagued Miami this season, it would be Sieler. 

That hasn’t been the case, though. He doesn’t have a single sack and has recorded just 11 pressures and three tackles for loss. Through seven games last season, Sieler had two sacks and 18 pressures. 

It’s been a step down in 2025, and defensive coordinator Anthony Weaver offered one reason that’s the case.  

“I think a lot of that is the partnership and cohesion with the guy he’s playing next to,” Weaver said. “We’re kinda in and out of putting outside backers in there, bigs in there. When you think about a lot of the success he’s had, it’s been with Christian Wilkins, a guy he could look at and know what you want to do. Calais [Campbell] has played at 45 years old. There isn’t a thing he hasn’t seen. It was easy for them to form that connection.” 

Weaver’s joke about Campbell’s age aside, it’s true that playing with standouts like Wilkins and Campbell is much different than playing with rookies like Kenneth Grant and Jordan Phillips. 

Sieler Lacks Comfort With New Linemates

Weaver isn’t the only coach on the Dolphins’ staff with this theory. Defensive line coach Austin Clark mentioned something similar during his media availability Thursday. 

“This is probably the first time, it is the first time in Zach's career in a long time, where you're playing with guys that you haven't necessarily played with before,” Clark said. You have training camp, but getting out there in heat of the battle… and running the games and rushing together.

“That's an area that we're forcing the issue to get better at, like, comfortability. When you go from playing with Christian and Calais to some younger guys, sometimes you could be trying to do too much, or you know, almost in a way, hesitant to do things you would normally do, knowing they would cover you up.”

Basically, Weaver and Clark’s argument for Sieler’s regression boils down to a lack of chemistry with his teammates, preventing him from capitalizing on stunts and twists when rushing the passer. 

There is definitely some merit to that. Sieler has won a lot of those reps for himself and his teammates over the years. However, it mostly ignores what he’s done with one-on-one reps, which make up the overwhelming majority of his snaps. 

The past two seasons, Sieler’s pressure percentage has hovered at around 10 percent, but this year it’s just 6. That indicates overall regression, not just the product of poor chemistry on designed stunts. 

How Run Defense Factors into Sieler’s Play 

Clark actually offered a second explanation for Sieler’s lack of production: a lack of pass-rush opportunities. 

“We're not doing well on defense, in terms of sacks in general, which is something we've known to see from Zach and a lot of our interior guys,” Clark said. “You first got to look to the number of opportunities where they're passing the ball, you know they're passing the ball, you know you're rushing the passer. So to me, like run defense is a part of that, which is an area where we're focused on getting better at.” 

Miami’s run defense indeed has been brutal this season, and that does tend to limit the number of obvious pass-rushing situations (third-and-long is just one example). 

The Dolphins are tied for 26th in the NFL in plays when the opposing offense is at third-and-6 or longer. That’s not a lot of chances for Sieler to pin his ears back and get after the passer. 

That said, it’s also important to note that Sieler is a primary reason Miami’s run defense has struggled this season. Coming into the year, holding the point of attack and being disruptive in the run game were two of Sieler’s better qualities. 

Sieler has taken a significant step back in both categories this season. On tape, it’s pretty common to see him getting moved out of his lane or collapsed down the line entirely. 

It’s a jarring thing to see, given that run defense has been Sieler’s most consistent trait through the years, while his pass-rush prowess mostly emerged the past two seasons. 

The hope is that as rookies like Grant continue to improve, Sieler can get back to his usual production. If that doesn’t happen, it’ll be tough for Miami’s defense to make meaningful improvements this season, and it’ll raise a lot of questions about Sieler’s future.