Cincinnati(CNN) After suffering a cardiac arrest during a game on Monday, Buffalo Bills safety Damar Hamlin remains in critical condition in intensive care, with "signs of improvement" noted over the past day, his team tweeted Wednesday afternoon, while uneasy supporters across the nation awaited word of his condition.
"He is expected to remain under intensive care as his health care team continues to monitor and treat him," the Bills said.
Hamlin, 24, has been at a Cincinnati hospital since collapsing during the Bills' game against the host Cincinnati Bengals on Monday night -- an incident that stunned a packed stadium and led to the game's postponement.
Hamlin's heartbeat was restored on the field as staff tended to him, the Bills have said, before he was taken to the University of Cincinnati Medical Center. Hamlin remained sedated on a ventilator as doctors worked toward getting him to breathe on his own, his uncle Dorrian Glenn told CNN on Tuesday.
Hamlin was resuscitated only once, a family spokesman clarified Wednesday, not twice, as his uncle told CNN on Tuesday.
"My nephew basically died on the field and they brought him back to life," Glenn said Tuesday.
It is still unclear what led to the cardiac arrest. CNN has requested comment from the hospital system, which is not releasing information about Hamlin or providing interviews with his medical staff.
Hamlin is on a ventilator to relieve some of the strain on his lungs, which have been damaged, according to Glenn. The doctors told Glenn his nephew has also been "flipped over on his stomach" in the hospital to help with the blood on his lungs, he said, adding, "It seems like he's trending upwards in a positive way."
Hamlin's cardiac arrest came as the NFL is under scrutiny for how it protects players in an inherently violent game. Hamlin collapsed shortly after a collision in which Bengals receiver Tee Higgins tried to power past Hamlin, who'd approached for a tackle, with about six minutes remaining in the first quarter of Monday's game. Hamlin still twisted Higgins to the ground and stood up -- but within seconds fell and lay motionless.
On-field injuries are not uncommon in the league, which often resumes play even after severe cases. Many current and former players strongly have supported the game's postponement, saying Hamlin's cardiac arrest felt especially disturbing as medical personnel fought to save his life while fans and players looked on.
As Hamlin was treated on the field, some players fell to their knees, sent up a prayer or were openly weeping and embracing one another. Bills offensive tackle Dion Dawkins realized the gravity of his teammate's condition when Hamlin stayed on the ground as more and more medical staff were called over, he said.
"In that moment, you're just thinking like, 'What can I do? What can we do?' And it just immediately breaks you down into prayer," Dawkins told CNN's Wolf Blitzer on Tuesday. "Whether you're a believer or not, only a higher power can really take control of what is next. And our people that help also assisted that higher power."
The incident marks the latest in a series of tragic blows for the Buffalo community, which in the past few months has endured a racist mass shooting and a historic blizzard that left at least 41 people dead in Erie County, New York. "It has been, you know, just (a) constant beating for Buffalo," Dawkins said.
A swell of support has surrounded Hamlin and his family as messages of prayers and well wishes have flooded in from star athletes, fans and national leaders. A fundraiser that Hamlin previously had started for his Chasing M's Foundation toy drive has raised more than $6 million since his hospitalization.
At a prayer service for the player Tuesday night, community members described the heartbreak of watching "one of our own" endure such a crisis.
"All you can do right now is pray for Damar: the man, not the football player, not the Buffalo Bill, but the person," the city's poet laureate Jillian Hanesworth said. "He has to pull through."
Monday's contest was postponed with the Bengals leading 7-3, and will not be resumed this week, and no decision has been made on whether to ever continue it, NFL have said.
"Everything is being considered," Troy Vincent, the NFL's executive vice president of football operations, told reporters Wednesday. One option mentioned in the news conference involved pushing back the start of the playoffs a week to fit in the rest of the Bills-Bengals game.
When asked whether the Bills will play the New England Patriots this Sunday, Vincent said league officials have not had that discussion.
"We'll allow (Bills head coach Sean McDermott) and his team and his staff and the players -- which are the most important thing here -- to guide us if we have to make that decision," he said adding it will be a collective determination between the NFL and the team.
"My concern is to make sure the men have what they need to function." he added.
Cardiac arrest results from electrical disturbances that cause the heart to suddenly stop beating properly, and death can occur quickly if help isn't rendered immediately. It is not the same as a heart attack or heart failure.
Dr. Allen Sills, the NFL's chief medical officer, told CNN Chief Medical Correspondent Dr. Sanjay Gupta on Wednesday that Hamlin's health care team will do everything it can to discover what caused his cardiac arrest but for now the focus is on helping him get better.
One possibility, although it is rarely reported in football, is commotio cordis, which happens when severe trauma to the chest disrupts the heart's electrical charge and causes dangerous fibrillations. Hamlin was injured while making a tackle and appeared to get hit in the chest.
"I don't think at this point we can rule (commotio cordis) out," Sills told CNN. Earlier, on the NFL's call with the media, Sills said it is a diagnosis of exclusion, meaning it might be the diagnosis if doctors don't find any other causes.
Doctors will look for any potential congenital or other abnormalities with Hamlin's heart, he said.
Hamlin, like every NFL player, had to pass health tests -- including an EKG -- to play this season. But sometimes players don't have a preexisting condition and cardiac arrest can happen without warning, the doctor said.
Hamlin was resuscitated just once after his collapse, his family's spokesperson said Wednesday. Glenn, the player's uncle, misspoke when he told CNN and ESPN the prior day that Hamlin had been resuscitated twice, spokesperson Jordon Rooney said.
"There's a lot of medical jargon, a lot of things being said, so Damar's only been resuscitated once," Rooney, Hamlin's friend and marketing representative, said Wednesday, speaking on behalf of the family.
"His uncle's incredibly supportive of his of his nephew. ... I think that, you know, he just wanted to do his part to share some good news, and I think just misspoke," Rooney said.
The family has said it is grateful for all the support it has received, including from the hospital, fans and the NFL community.
"(They are) incredibly thankful of everything that has been out there, all of the support that they've gotten. It's made this just a little bit easier for them," Rooney said Wednesday. "They're very grateful people, and it's meant a lot to them."
Higgins, the receiver involved in the collision that preceded Hamlin's collapse, has reached out to Hamlin's family and been supportive, Rooney said.
This story has been updated to reflect the number of times Hamlin was resuscitated based on information from a family spokesperson and his uncle.