In 2018, the Dallas Cowboys defense was one of the NFL's best ranking seventh overall (5th vs run, 13th vs pass). This season, the numbers were again really good as the Cowboys defense finished ninth overall (11th vs run, 10th pass). However, they were misleading if you actually watched the games. Several slow starts defensively allowed teams to build leads on the Cowboys that were too much to overcome.
Just a few weeks ago, Mike McCarthy was hired as the new head coach. Before the news could even begin to register, McCarthy started fine-tuning the coaching staff. Not a complete overhaul, but there were very few holdovers from the previous era under Jason Garrett.
The first domino to fall was bringing in long-time assistant Mike Nolan as the new defensive coordinator. Nolan has 32 years of NFL coaching experience having been a part of 10 different organizations including seven gigs as defensive coordinator. He spent the last three years as the linebackers coach for the New Orleans Saints.
The Cowboys will still run their base 4-3 defense as opposed to the 3-4 Nolan has traditionally operated with. He has a history of producing good linebacker play. As the head man for the San Francisco 49ers, retired linebacker Patrick Willis was an all-pro and one of the best at the position under Nolan. Also, Demario Davis of the Saints was an all-pro in 2019 under the guidance of the Cowboys new DC. Now, he gets to work with Jaylon Smith and Leighton Vander Esch, and maybe even Sean Lee if he returns next season.
Jim Tomsula will coach the men upfront in 2020. He's no stranger to working with the aforementioned Nolan, having served as his defensive line coach during the 2007 and 2008 seasons with the 49ers. Tomsula held that role for eight years in San Francisco and helped produce some of the NFL's best defenses from 2011-2013.
He will be joined by Leon Lett who will return for his 10th season as the assistant defensive line coach for the Cowboys. Having coached names such as DeMarcus Ware and DeMarcus Lawrence, Lett can be a great asset to what Tomsula wants to do in the trenches.
Just recently the second level of the defense got a few new faces to guide the ship. Scott McCurley, who worked under McCarthy during his entire tenure in Green Bay, will coach the linebackers. McCurley started out as an intern with the Packers in 2006 before being named Coaching Administrator a year later. In 2014, he was named the linebackers coach where he assisted Winston Moss.
Another addition, just in the previous few days, was long-time assistant George Edwards as the team's senior defensive assistant. He's no stranger to the organization, having served as the linebackers coach from 1998-2001. The previous six years Edwards was the defensive coordinator for the Minnesota Vikings, who have routinely produced some of the league's best defenses recently. Now, Edwards will team with McCurley in guiding the linebacker group, with the former reportedly having a much larger role that will be detailed at a later date.
The secondary will also have new leadership. Maurice Linguist, who spent the previous two seasons at Texas A&M, was brought in to coach the defensive backs. Linguist comes into the NFL with over a decade of secondary coaching experience on the college level.
Even though this will be Linguist's first year on the professional level he won't be alone, with the addition of Al Harris as an assistant secondary coach. Harris played under McCarthy for five seasons in Green Bay from 2006-2010. He was a coaching intern for the Miami Dolphins in 2012 before spending six years as an assistant secondary coach for the Kansas City Chiefs from 2013-2018.
To answer the question, yes I believe this new staff will get the Cowboys defense back to consistently being good week to week. The combination of talent on the roster and the experience of these defensive coaches gives plenty of room for optimism going forward.