NFL chief medical expert explains Tua Tagovailoa's decision of not wearing the Guardian Cap

Tua Tagovailoa will return to the NFL on Sunday, wearing his normal helmet without the Guardian Cap. This decision is considered the top-of-the-market for quarterbacks, reducing head-impact severity. Tagovailoa is recovering from his third known concussion in his career and will start against the Cardinals 45 days after suffering the concussion in Week 2. He wears a VICIS ZERO2 MATRIX ID QB helmet, a modification of a helmet the league has deemed "Guardian Cap optional."

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NFL chief medical doctor Allen Sills on Tua Tagovailoa not wearing the Guardian Cap

"For most helmets adding a Guardian Cap, an extra layer of padding, will reduce the force of each blow by somewhere between 10 and 15%," NFL chief medical doctor Allen Sills told CBS Sports. "Now there is a subset of helmets that we tagged as Guardian Cap optional. And the reason for that was that those helmets in the laboratory testing showed that there really was not additional benefit of that magnitude by adding a Guardian Cap."

He continued, "In other words, the helmet itself was doing as good a job of mitigating the force as a regular helmet plus a guardian cap. So adding a Guardian Cap to those helmets did not show that same 10 to 15% benefit.” The VICIS ZERO2-R MATRIX ID is an optional Guardian Cap helmet, while Tagovailoa's helmet is a quarterback modified version with occipital padding for better head protection against typical head blows.

Scientists test helmets in labs by mimicking field collisions with force, direction, and speed in professional football. Helmets are ranked based on their force reduction effectiveness and compared to data from RFID tags in players' helmets, allowing the league to understand the rate of force on the field and diagnosed concussions. "Because we tag every helmet that every player's wearing, we know exactly the concussion on-field rate for every single helmet, and we can go back and compare that to the lab data," Sills said. "And so that's why we have a lot of confidence in that lab data.”

No quarterback has worn a Guardian Cap in-game this season, despite approved helmets. The cap adds 0.8 pounds in weight and is considered a personal choice by quarterback Tagovailoa, who declined to wear it. Sills and the NFL maintain that Tagovailoa's return is a patient-medical decision, as the league does not practice medicine. "I have absolute confidence in the Dolphins medical staff," Sills said, "that they are being as thorough and conservative as possible, and that they have deployed all of their local as well as internationally renowned resources to provide this player with the very best of care and to make sure that all information is available for decision making.”

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