Toronto Maple Leafs forward prospect Rodion Amirov, who was the club's 2020 first-round pick, has died, his agent Dan Milstein confirmed Monday. He was 21.

Milstein posted on X, formerly known as Twitter, that Amirov died after being diagnosed with a brain tumor.

"From the moment he received the news, he refused to speak in the negative, determined to enjoy every day, facing it with the same positive attitude he showed during his hockey career," Milstein said in a statement. "We will always remember his courage, his desire, his will, his smile, all of the great things about him."