Heyward-Bey was carted off the field after taking a knee from Vikings linebacker E.J. Henderson to the back of his head as he was being tackled at the end of a 4-yard reception early during the fourth quarter. The force of the impact actually knocked Heyward-Bey's helmet off.
Jackson said the team would "continue to monitor" the injury but he was hopeful Heyward-Bey would be able to play again this season. Heyward-Bey had initial movement in his arms and legs before trainers made their way to the field, and Jackson confirmed the receiver was alert and had full movement after the injury.
"I saw him out there and talked to him. He's going to be fine," Jackson told reporters. "I really, truly believe he's going to be OK, but obviously we have to take all the precautionary measures to make sure he's going to be OK."
Heyward-Bey was immobilized on a backboard and loaded onto the cart following the play, and at one point raised his left fist to the cheering crowd. The team announced he was later taken to a hospital for observation. Heyward-Bey was later released and flew home with the Raiders, according to Comcast SportsNet Bay Area.
Henderson said he hoped to reach out to Heyward-Bey to make sure he was OK.
"As soon as you see the cart out there, it's a bad feeling," Henderson said. "Hopefully he is OK. He gave us the thumps up when he was leaving the field."
The Associated Press contributed to this report