In 2022, Tua (the QB for the Dolphins) suffered a concussion one week and was held out for a time, then came back and suffered a severe concussion, which resulted in him displaying the "fencers pose" (which is NOT a good thing).
He played sparingly for the remainder of the season, and "came back strong" in 2023. He credited weight training and judo for making his stronger. And behold! While he was hit several times in way that probably would have caused a concussion, he was never diagnosed with one.
Aside: I posit that there was also a change in the way concussions were evaluated, at least in part to keep players on the field.
He's a below-average to average QB in the league, but the Dolphins decided he was worth investing in (at least in part because the owner is an idiot, but that's a story for another day) and gave him the equivalent of about 20% of all the salary cap. Most of the $50 million per year over 5 years, guaranteed.
Week 1, he has an average day and mostly underperforms.
Week 2, he starts off very slow. Doesn't look "sharp" and throws three interceptions.
And then in the 3rd quarter, he's diving for yardage - stupidly - and runs into a defender, his head gets bent sideways and he winds up on the ground with a severe concussion and the "fencers pose" once again.
So now it's a question about health and safety. Sure, it's been 2 years since his last diagnosed concussion (or at least severe one), but in between he's taken hits, and undoubtedly the trauma has built up.
And longer term, should he continue to play? Will he try and come back? And what of the significant amount of money he is owed? Will that hold the team back for a very long time?
On a more amusing side note, what if the no-name low-paid backup has success? What does that say about the team and its decisions?