How the 49ers' Defense Can Adjust Without Kwon Alexander

The loss of linebacker Kwon Alexander is a huge blow to the defense of the 49ers, but there are a couple of ways they can adjust without him.

Just when things were going so well for the San Francisco 49ers, the domino effect of injuries to their key players struck again. The latest victim is linebacker Kwon Alexander who suffered a torn pectoral muscle in the fourth quarter in the team’s 28-25 win over the Arizona Cardinals on thrusday night. 

Alexander will miss the rest of the season to recover his injury. His loss to the 49ers’ defense a huge blow. Alexander established himself as a leader of the defense and backed it up with his elite play in pass coverage. Pro football focus had him ranked as the second best coverage linebacker in the league.

Now that he is gone, the 49ers’ defense must adjust. As good as Robert Saleh is as a coordinator, he faces a difficult task in trying to fill Alexander’s shoes. The only question is how do they adjust without him?

Next Man Up

The next man up to replace him will be rookie Dre Greenlaw, though I wouldn’t necessarily say it is absolute. Saleh can definitely rotate Greenlaw with Azeez Al-Shaair when he sees fit. You should also expect the 49ers to promoted Elijah Lee from the practice squad to provide them depth at linebacker. 

Greenlaw is likely the best suited to replace Alexander since he can replicate his speed. It’s why he was so astute in pass coverage to immediately snuff out passes. In fact, Greenlaw has actually been clocked at speeds going 21.2 mph. It is simply unheard for such speed as a linebacker. Greenlaw has the skill set to fill in for Alexander, it’s just a matter on if he has the right mindset. 

Will he be able to step up in key situations? That is the critical question because offenses will now look to test him out immediately. You better believe that Russell Wilson will be making a note of it when his Seahawks come to Levi's Stadium on Nov. 11. Alexander was a very intelligent player which, on top of his leadership, is the real challenge to replacing him. 

On a positive note, the development for Greenlaw is going to accelerated. He could very well turn into a diamond in the rough finding for the 49ers. That isn't to say he isn't talented, but that for all we know he could turn into a star. Just look at how all the other backup players have stepped up in their roles to fill in for injured players. The evidence is all over the place and it is indicative on the talent evaluation of this staff.

Utilize Big Dime

If Greenlaw and the other linebackers are struggling mightily, then Robert Saleh could start to utilize more big dime formations. For those unfamiliar, it is still the same concept as a standard dime package, except a safety is implemented as the sixth defensive back. The 49ers' defense can still have two high safeties and three corners like a nickel formation. Fred Warner will anchor the linebacker spot, while the other "linebacker" spot is filled by a safety. 

Both Jimmie Ward and Jaquiski Tartt are capable of playing that box safety role to lurk in coverage. It is not like their toughness will be called into question as they are both hard hitting, sure tacklers. They also meet the requirements for speed since they will not be a mismatch for running backs. The glaring issue is that they will be increasingly vulnerable to the run. 

Offensive lineman will have there way with them on the second-level or if they try to meet the runner in between the tackles.However, David Lombardi of The Athletic brought up some brilliant points regarding the rush defense of the 49ers. In years prior, they were stout in rush defense, however this season it has worsened due to the focus on defending the pass.

There are valid reasons for this: Schematically, the 49ers have shifted a greater emphasis on playing the pass, both with Wide 9 DL alignment and with personnel choices. These have paid off big-time in the coverage game, as Alexander and Warner are both top-10 in that regard...

— David Lombardi (@LombardiHimself) November 1, 2019

The 49ers just put on display how shaky their run defense is against the Cardinals. They allowed Kenyan Drake, who just arrived to the team days before, to run all over them. Sure, it was a short week, but there has been evidence that offenses can attack the 49ers' defense by running the football. So why not just put in a safety at the linebacker position? It isn't the ideal scenario to play dime, but it is an option in case Greenlaw and co. cannot fill in sufficiently. 

This is why it is a tough task for Robert Saleh. There is going to be a lot of tinkering if they do not find the right fit. Don't get me wrong, this defense is still elite. But with Alexander gone there is now a weakness that offenses will look to exploit. The Seattle Seahawks will get there first crack at the 49ers without him. Luckily for them, they have a few extra days to prepare for that matchup.