This offseason, the NFL approved a new rule change to low blocks that limit their use to a box that’s two yards outside of the tackle and five yards on either side of the line of scrimmage from which they can be initiated. Low blocks are illegal by any player everywhere else on the field during a scrimmage down.
Inside the box, blocks below the waist may be initiated except on blocks already illegal, such as crackback blocks.
Here’s the new low block rule, which expands the prohibition against blocking below the waist. pic.twitter.com/lxxpB6fBrz— Tom Pelissero (@TomPelissero) May 26, 2021
The new rule will have a greater impact than is realized by fans. For example, while already illegal on special teams and changes of possession, low blocks were legal prior to the rule change this offseason.
Now, they’re illegal on all scrimmage downs outside of a designated area, which will have far-reaching impacts on offensive schemes that rely on blockers on the perimeter and into the boundary on running plays, particularly teams that like to run outside zone.
Low blocks are commonly used by offensive blockers in space downfield on completed passes, plus on screen passes, as linemen and receivers clear a lane for the ball carrier and on the edges or perimeter of a run play to clear space for the running back.
A player’s perspective
To get some player perspective on the rule change, I spoke with nine-year NFL veteran and former San Francisco 49ers offensive lineman Mike Person about how the rule would broadly affect how teams execute their offensive scheme and, in particular, how it would affect players.
Person spent nine years in the NFL with 49ers, whom he was drafted by, then spending time with Seattle, St. Louis, Atlanta, Kansas City, Indianapolis, and finally returning to San Francisco in 2018 — where he started at right guard for two seasons, including during the Super Bowl 54 run.
Person, who retired in the spring of 2020, coaches and now runs the 5 Dot Offensive Line Academy in Dublin, Ohio. He teaches high school and some middle school offensive linemen the finer points of playing the position.
Throwing a low block is coached in each individual scheme and is instinctual to playing offense, particularly for offensive line players. It is ingrained in a sport to the point that it becomes a necessity to throw a low block. “In the 49ers scheme, it’s not a requirement. We do it because oftentimes we’re taking on smaller, faster corners on the edge and the only way to block some of them is to go low,” Person stated. “In some schemes, we’re taught to go low and get low in space. Some offensive line coaches want you to do it.”
The goal when going low is to clear space for the ball carrier. In the clip above, Person, who is accustomed to run blocking in space in the 49ers outside zone running scheme, can be tasked with blocking anyone from the first down lineman to his side on the play side to a linebacker trying to fit the B-gap to a corner out on the edge in a toss play.
In general, linemen usually have to block corners and safeties on the perimeter, and throwing a low block is the easiest way to do it. The play is executed perfectly, and no one throws a low block.
“We want to disrupt their path mainly. And also because bigger guys like me obviously aren’t as quick as those smaller defenders. It makes our job easier. We’re taught if we’re going to go low, to aim at the thigh pads of the defender and disrupt his path. Even if we miss, the goal is still to disrupt and throw him off his angle.”
In the clip above, the low block executed by center Ben Garland downfield on Saints defender Marshon Lattimore would now be considered a foul in 2021. As a result, explosive plays like this would be negated due to the foul occurring outside the designated tackle box.
Throwing low blocks can also be detrimental to the offense if not executed properly. Some coaches are wary of the technique being used as it can sacrifice the integrity of the run play in particular. Person adds, “With the 49ers, Kyle (Shanahan) primarily wants the run to get to the edge as far as possible, so he doesn’t want the backside blockers cutting down the defenders because if we miss, they can chase down the back as the play develops.”
On the front side of the play, throwing low blocks or cutting defenders inside the tackle box can create chaos and disrupt the play's timing and clog running lanes and “slow down the play’s development,” allowing other unblocked defenders to rally to the ball carrier quickly.
Person also stated that he thinks the rule change will ultimately lead to offensive linemen having to adapt how they block in space “by adjusting our aiming point higher on the defender. As linemen, we’ll have to adapt and learn how to get super detailed with our blocking in space.
This will also impact players because smaller offensive receivers and tight ends may have a hard time engaging defenders in space if they’re not already skilled at “stalk” blocking. Stalk blocking is a tough technique to execute if a receiver isn’t in a position and under control to engage a defender from the waist up to the chest.
Receivers are also now not allowed to throw a low block on a crackback block inside the tackle box but can throw them on sift blocks on the backside of a running play. In the play above, with a coaching point from the late Alex Gibbs (father of the modern-day outside zone) dubbed over it, smaller receivers, tight ends, and the fullback all execute to perfection even though some have to take on bigger defenders in space. Coaching matters in the 49ers scheme. In particular, players may not have a hard time adapting at all.
It’s tough to know for sure how this will affect non-offensive line players. Coaches may start examining who outside of their top one or two wide receivers is worth keeping around if they cannot properly block without throwing a low block on the perimeter or downfield. On the other hand, players not skilled at the finer points of blocking could find themselves on the cusp of losing a roster spot.
In addition to offensive players, defensive players are also not allowed to throw a low hit below the waist to take out a blocker coming to meet them. Typically, defenders will execute this technique to throw off the timing of the play and disrupt a blocker's ability to get in space. Now, defenders will have to engage blockers or beat them to the point of attack to make a tackle or force or spill the ball carrier back to the rallying defenders.
All of this is covered for players in camp. “We have about an hour-long meeting when the NFL officials are in town, and they go over all of the new rules changes.” In addition to this, during practice, NFL officials will flag players for rules infractions. “A quality control coach will write it down on the play sheet, so we know when we see it while we are watching the film from practice.”
Person concluded by adding that, “I can definitely see a scenario in the future where they’re eliminated. The league seems to be trending that way over the last few years as they prioritize player safety.”