The Iowa defense has been successful since the Kirk Ferentz era began in 1999. A large part of that success is the defensive coordinator Phil Parker. Parker has been the anchor of the defense and secondary since joining Ferentz in 2012.
Phil Parker's predecessor, Norm Parker (no relation), was a big proponent of the base 4-3 defense, employing four down defensive linemen and three linebackers. Phil continued that scheme until a minor shift to a 4-2-5 scheme in 2018.
The base four down linemen is the same, but the back end changes to accommodate the ability to cover more receivers.
Since shifting the scheme in 2018, the Hawkeyes have ranked in the top ten in opponents' points per game in four of six seasons. The 4-2-5 zone scheme adds more defensive backs to the secondary, where they each cover a fourth of the field with two deep safeties over the top.
The scheme also utilizes a "Cash" defender as a slot corner or outside linebacker. Since adding the "Cash" defender, the defenders to play the position, including, Amani Hooker, Dane Belton, and Cooper DeJean, have all had successful NFL careers.
The scheme depends on everyone playing their zones effectively, keeping their eyes on the quarterback.
After losing multiple pieces in the secondary, the Hawkeyes' defensive back room will look different this season.
Iowa has three defensive backs locked in as starters, including Xavier Nwankpa (free safety), TJ Hall (cornerback), and Deshaun Lee (cornerback). Hall and Lee must improve for the secondary to improve. When starting defensive back Jermari Harris was sidelined, the duo was leaky and inconsistent.
With Nwankpa shifting to the free safety position, the strong safety position is opened. Newly acquired transfer defensive back Shahid Barros is projected to occupy one of the open DB spots, but can also slide into the strong safety slot.
If Barros moves to the safety position, the Hawkeyes will have two heavy-hitters on the back end. That leaves one more cornerback spot and the "Cash" position. Zack Luttmer and Koen Entringer played the "Cash" position last season and can fill the vacant spot.
Whoever does not serve as the "Cash" defender between Luttmer and Entringer can slide to the third cornerback slot. After receiving quality snaps as a freshman, Jaylen Watson will also factor into the decision.
The Hawkeyes will look different in the secondary, but defensive wizard Phil Parker always gets the most out of his players.