Alex Smith never saw the hit coming. He knew the protection around him had broken down, and he saw defenders converging upon him. Then he felt it. A tug from behind, then a crushing weight from above. Milliseconds unfolded in slow motion. “I’ve got a human being on my back,” Smith realized, “in the middle of a football game.”

A 284-pound human. Aaron Donald of the Los Angeles Rams — the most dominant defensive lineman in the NFL — had jumped on Smith’s back to bring him to the ground.

A football game. Smith’s first in 693 days. This was his first hit since the tackle that shattered the bones in his right leg, which doctors at one point worried they would have to amputate. The leg. Smith, with Donald still on his back, realized the same leg that endured 17 surgeries and hundreds of hours of rehab, bore the bulk of the body weight of two people. After collapsing and then getting back up, he realized the leg felt good. It was fine. He was fine.