August 30, 2015; Oakland, CA, USA; Oakland Raiders defensive coordinator Ken Norton Jr. during the third quarter in a preseason NFL football game against the Arizona Cardinals at O.co Coliseum. The Cardinals defeated the Raiders 30-23. Mandatory Credit: Kyle Terada-USA TODAY Sports

The time has come. After two seasons as the defensive coordinator, Jack Del Rio and the Oakland Raiders need to end the Ken Norton Jr. experiment.

February 6, 2015 — Ken Norton Jr. is hired by Jack Del Rio to be newest defensive coordinator of the Oakland Raiders. After five seasons as the linebackers coach of the Seattle Seahawks, Jack Del Rio tabbed Norton Jr. to lead Oakland’s defense, to the delight of many in Raider Nation.

Norton Jr. enjoyed much success as the linebackers coach in Seattle, helping groom and develop the Seahawks linebackers into a formidable group. As a player, Norton Jr. enjoyed 13 productive seasons as a linebacker himself, so given how much time he had spent around football, many expected him to be a fantastic coach.

Fast forward less than two years later, and it’s time for this experiment to come to an end. The Raiders should fire Norton Jr. after two seasons of underwhelming defensive performances.

Norton replaced Jason Tarver, whose defense ranked 21st in 2014. Tarver’s group included starters such as Miles Burris, D.J. Hayden, Brandian Ross and Ray-Ray Armstrong. Norton’s 2015 group was noticeably more talented at every level of the defense, and they fell one spot year over year, to the 22nd ranked defense under Norton.

The 2015 defense ranked 26th in passing defense, 13th in rushing defense, and 22nd in points allowed. They were 19th in sacks and 12th in takeaways. Seven times, the defense allowed 29 or more points.

So let’s just give Norton a pass for his first season as a coordinator. The defense wasn’t downright terrible, and it’s reasonable to say that some time is needed to develop. Like players, coaches can get better (or worse) with time.

2016 — Norton’s second season as the defensive coordinator, expectations were high coming into the season.

The Raiders had signed free agent cornerback Sean Smith, one of the highly sought after players on the market. They brought Reggie Nelson on board, who had just led the NFL in interceptions the seson before. They drafted Karl Joseph with the 14th overall pick, and they also signed Bruce Irvin to complement Khalil Mack as a pass rusher.

The new additions to the defense would be joining some of the notable players already on the defense — Khalil Mack and David Amerson, among others. With a healthy supply of talent at his disposal, there would be no excuses for a poor performance by the defense.

Then Week 1 happened.

Oakland’s revamped secondary was completely and utterly torched by Drew Brees and the New Orleans Saints, to the tune of 423 passing yards on 28 of 42 attempts, 4 TDs and 0 INTs. Willie Snead hauled in 9 catches for 172 yards and a TD. Brandin Cooks racked up 143 yards on 6 catches, and he added two scores. Michael Thomas pitched in 6 catches for 58 yards.

The newly acquired Sean Smith had it the worst, and was benched in the game. The pass rush only sacked Brees one time.

The run game contributed 88 yards of their own, with a 4.0 yards per carry average, giving the New Orleans offense a grand total of 507 yards of total offense. The Raiders offense carried the team to a win, but the defense surrendered 34 points.

It was a disastrous way to the start the season. But let’s just say it was a fluke, or maybe that the defense still needed some time to gel. Or whatever excuse you would like to add.

Then Week 2 happened.

Oakland’s defense was once again torched, this time by Matt Ryan and the Atlanta Falcons. Ryan threw for 396 yards and 3 TDs, completing 76 percent of his passes along the way. Julio Jones did Julio things, with 5 catches for 106 yards and a TD. Atlanta’s trio of tight ends — Hooper, Tamme, Toilolo — combined for 10 catches for 180 yards and a touchdown.

Devonta Freeman and Tevin Coleman combined for139 yards on 29 carries (4.8 YPC), with Coleman adding a touchdown. This gave the Falcons a grand total of 528 yards of total offense.

Uh oh.

This was a historically bad start, breaking a record of yards allowed through two games — a record that had previously stood for 65 years. Oakland’s defense would see some improvements — although improving from a historically bad start isn’t saying much.

Here are the yardage allowed totals for the rest of the year, in chronological order — 393, 412, 423, 406, 344, 270, 299, 254, 358, 382, 323, 263, 390, 349.

It took until Week 8 for the Raiders defense to allow less than 344 yards. They allowed under 300 yards just three times, against the 14th, 18th, and 27th ranked offenses. Norton’s defense gave up 382 or more yards eight different times.

The pass rush was nearly non-existent outside of Khalil Mack, finishing with 25 sacks as a team — dead last in the NFL. Mack accounted for 44 percent of the team’s sack production, which is both absurdly impressive for Mack, and absurdly sad for the rest of the defense.

Oakland’s defense was also the 4th most penalized defense in the league, with 1,051 yards on 115 penalties.

Another reason why it’s time to move on from Norton is due to his lack of adjustments. From both throughout the season, and also simply from the first half to the second half of a game. No team in the NFL surrendered more points in the 3rd quarter than the Raiders.

Even beyond the numbers, there is plenty of reason why Norton has to go. His situational play-calling is a disaster — such as not knowing when to blitz and when not to blitz, and he doesn’t understand the strength of his personnel.

Too many times, Sean Smith would play off-coverage. Anybody that has ever watched Smith play football knows he is a press-man cornerback. If you play him five or more yards off of the wide receiver he is covering, he is going to get torched. Which he did. Often. And honestly, you don’t even have to have seen Smith play to know that — just look at the guy, he’s massive.

Too many times, Norton also used Reggie Nelson as a single-high safety. Watch one game of Nelson in 2016 and you’ll see why that’s a bad idea.

Too many times, Norton put Malcolm Smith in one-on-one coverage with a player that he was clearly outmatched by. Too many times, even Khalil Mack was dropped in coverage, defending someone he had no business covering.

So for all of these reasons and more, Ken Norton Jr. has to go. It appears that Del Rio already may know that.

JDR, if he anticipates making staff changes after keeping it together last year. Didn't answer directly. "We have a good group. They care." — Scott Bair (@BairCSN) January 8, 2017

Del Rio’s noncommittal response about potential coaching staff changes really says everything there is to say — the writing is on the wall. Instead of providing a vote of confidence in his defensive coordinator, he instead gave a canned response that in no way answered the question that was asked.

And if there are any truth to the rumblings, Wade Phillips could be an option to replace Norton as the defensive coordinator. And even if not Phillips, there will be several other coaches available that will be an upgrade over Norton. Even an internal promotion to someone such as Jethro Franklin would be an upgrade.

This type of news typically breaks early following the end of a season, so stay tuned in the upcoming week to see if anything happens.