Other people believe Hamlin is not alive because there have been very few clear photos of his face in public since the incident.
"The real Damar Hamlin is dead. He has been Cloned. He died on the field, why do you think the rest of his teammates haven’t been talking to him?" A Twitter user wrote on Monday.
\u201cSomething isn\u2019t right. Nobody has seen or heard from this man publicly and these recent pictures are all suspect. Is this what they mean \u201cDamar Hamlin is flying under the radar\u201d? Looks like a completely different person to me. But what do I know. Hopefully I\u2019m wrong\u2026 \ud83e\udef6\ud83c\udffe\u201d
On Sunday night, Hamlin made an appearance at the Bills versus Bengals game to show support for his team.
According to the Bills, he made a "special visit" to the locker room to greet his teammates, three weeks after he went into cardiac arrest.
Head coach, Sean McDermott, said his presence was "good for the guys" and a "pretty cool moment."
Fans could spot Hamlin making a heart with his hands and hyping up the Bills during the game.
But because the football player kept his coat hood up and sunglasses on it made it difficult to see his face clearly, only adding fuel to the fire of conspiracies.
\u201cNo oxygen tank. No interview. No clear visual of Damar Hamlin's face. Weird.\u201d
— The Sly Show\ud83c\uddfa\ud83c\uddf2 (@The Sly Show\ud83c\uddfa\ud83c\uddf2)
\u201c@BuffaloBills @HamlinIsland I still believe he died the NFL is covering up for LAW SUITS NO VIDEO OR PICTURE OF HIM IN HOSTPITAL OR LEAVING ALWAYS COVERING HIS FACE OR SEEN FROM DISTANCE\nI'll bet this off season they will say he passed away of something else\u201d