Warning: This video contains footage that may disturb some viewers.
Dallas Cowboys quarterback Dak Prescott has suffered a horror ankle break during his team's NFL encounter with New York Giants.
Prescott had just steered his team to a 24-23 lead over their rivals in the third quarter, when he fell awkwardly in a tackle, with his right ankle pinned underneath Giants defensive player Logan Ryan.
The game stopped for several minutes, as he was attended on the field and eventually carted out of Arlington's AT&T Stadium, waving as he left, but obviously distressed.
Among the first to check on his health was former Cowboys head coach Jason Garrett, now Giants offensive coordinator.
Fellow players from around the league immediately posted on social media, offering condolences and best wishes for Prescott's recovery.
The Cowboys have announced he suffered a compound fracture and dislocation, and ESPN reports he will undergo surgery on Monday (NZ time). With back-up Andy Dalton replacing Prescott, Dallas kicked a field goal with time up to beat New York 37-34.
"I feel terrible for him," Cowboys coach Mike McCarthy says. "He was having a tremendous year.
"He's made such an impression on me. He's the leader of this team.
"This will just be another chapter in a great story. He's a fine young man."
Prescott has played for Dallas since 2016, when he was named NFL Rookie of the Year. He has made two Pro Bowl appearances (2016, 18) and during the past off-season, the Cowboys re-signed him as their 'franchise player', worth US$31.4 million (NZ$47.1m) for the current season.
Last week, he became the first player in NFL history to pass for at least 450 years in three consecutive games.
"Yeah, it sucks," says star Cowboys running back Ezekiel Elliott. "I know we won, but it just sucks to lose Dak, our leader.
"I was talking to the guys and it's going to take all of us to fill that void that we're going to be missing from [No.4]. We just gotta go out there and play for him."