Welterweight world champion Errol Spence Jr has been taken to the intensive care unit of a Dallas hospital following a car crash in the city.
Spence, who holds the IBF and WBC belts, was injured in the early hours of Thursday morning while driving a white Ferrari, which was pictured with significant damage.
Dallas Police confirmed the 29-year-old, who they said was not wearing a seatbelt at the time of the crash, had been hospitalised but was "expected to live".
A statement from Dallas Police said: "On October 10, 2019, at 2:53 a.m., a white Ferrari was travelling at a high rate of speed northbound in the 500 block S. Riverfront Boulevard. The Ferrari veered left over the centre median onto the southbound lanes and flipped multiple times ejecting the driver who was not wearing a seatbelt.
"The driver, Errol Spence, Jr., 29-years-old, was taken to an area hospital where he remains in ICU. He is expected to live. The cause of the accident is undetermined at this time."
In September, the unbeaten Spence defeated Shawn Porter by split decision in Los Angeles to defend his IBF title and also claim the WBC strap.
Porter was among those to wish his welterweight rival well, posting on Twitter: "My dad always tells me, 'This boxing thing is a part of your life but it's not going to last forever. You still have a lot of life to live after that'.
"With that, I'm praying for @ErrolSpenceJr and his family because he has a lot of life to live and I pray he recovers quickly and fully."
WBO champion Terence Crawford has been involved in a public back-and-forth with Spence concerning a potential unification bout, but he sent his best wishes on Thursday.
"Praying for you champ, @ErrolSpenceJr," he wrote on his own social media page. "Get well. We fighters - I know you will."
Kell Brook, who was dethroned as IBF champion by Spence in 2017, posted his own message, writing: "Get well soon champ! Thoughts are with you and wishing you a full and speedy recovery."
Manny Pacquiao, the only eight-division world champion in the sport's history, tweeted: "Praying for @ErrolSpenceJr.."