NEW YORK (AFP) — Buffalo Bills safety Damar Hamlin, who suffered a cardiac arrest during a National Football League game, was improving Wednesday but still in critical condition as other players began preparing for weekend contests.

The 24-year-old defensive back collapsed Monday night after receiving a hard hit in the chest while tackling Cincinnati receiver Tee Higgins during the first quarter.

Medical workers restored Hamlin's heartbeat on the field and he was taken from the stadium to a hospital by ambulance, while the game was halted with the host Bengals leading 7-3.

"Damar remains in the ICU (intensive care unit) in critical condition with signs of improvement noted yesterday and overnight," the Bills said in a statement.

"He is expected to remain under intensive care as his health care team continues to monitor and treat him."

Fans gathered outside the Bills' home stadium to conduct a prayer vigil for Hamlin.

"Right now, things are moving in a positive direction," said Jordon Rooney, a friend and marketing representative of Hamlin.

United States President Joe Biden spoke at length with Hamlin's parents and told reporters when asked about the NFL that "it is dangerous. We've got to just acknowledge it."

NFL players returned to workouts on Wednesday ahead of the final weekend of regular-season games, with the New England Patriots set to visit the Bills on Sunday.

"We're all handling it in different ways," Bills offensive tackle Dion Dawkins said.

The Bills conducted team meetings and a walkthrough practice session Wednesday but media sessions were canceled.

NFL executive vice president of football operations Troy Vincent said NFL officials have not spoken about canceling the Bills-Patriots game but said Bills coach Sean McDermott and Buffalo players will guide such matters.

"We've not had that discussion," Vincent said.

"We'll allow Sean, his team, his staff and the players — which are the most important thing here — to guide us if we have to make that decision."

The NFL said the Bills-Bengals game, a key game for playoff seeding, will not be completed this week and might never be finished.

"Everything is being considered," Vincent said.

An NFL spokesperson said a decision would be made "in the coming days" in consultation with the Bills and Bengals.

Cincinnati quarterback Joe Burrow said his team will support whatever the Bills decide.

"Whatever Buffalo would want to do would be what we would want to do as well," he said.

"We're behind them 100 percent in whatever they decide."

In the meantime, NFL players still coping with the shock of Hamlin's injury were preparing to return to the gridiron. That included the Bengals, who entertain Baltimore on Sunday.

"It's a weird feeling going back to business as usual," Burrow said.

"Unfortunate as it is, we've got a game to play on Sunday. I don't know what to say. It's such a scary, emotional time."