Auer was involved in a massive crash shortly after setting the fastest time in the opening practice session on Thursday, the DTM ace having to be retrieved from his car after smashing into the concrete wall near Turn 2.
The Austrian driver was subsequently transported to hospital and is understood to have suffered fractured vertebrae, which will require surgery as per standard procedure.
Due to the extent of the injuries, it was clear that Auer will not be able to take part in the remainder of the weekend, with the Winward team confirming his absence to Motorsport.com on Friday.
The outfit has elected to promote 32-year-old Morad, who had originally been signed to compete in IMSA Michelin Pilot Cup Challenge in a GT4-spec Mercedes-AMG, as Auer's replacement.
Morad will join Russell Ward, Philip Ellis and Indy Dontje in the #57 Mercedes-AMG GT3 for what is the opening round of the 2023 IMSA WeatherTech SportsCar Championship season.
This won't be the Canadian's maiden outing in IMSA's top series, having previously made a trio of GTD appearances with Alegra Motorsport in the same AMG GT3 last year.
"We have Daniel replacing Lucas, Daniel Morad. He is now in GT4 with the father of Russell [Ward, team owner Bryce] and he will be taking over the seat from Lucas," Dontje told Motorsport.com.
Dontje also confirmed that Winward has successfully sourced a spare car from the team's base in Houston, some 1400km from Daytona International Speedway, and is confident that it will perform as per expectations.
"The car is arriving after lunch, I think after 2 o'clock," he revealed. "The team is motivated to get the car ready, I think everyone is positive from that side. Just hope we can do one hot lap. The safety of the car is all okay, it needs some little stuff to be done.
"The car is from last year, it should be good. The [previous] car was also running really good up until the crash. We are still positive."
Despite losing a driver of Auer's calibre from the line-up, Dontje remains upbeat about Winward's chances of defending its GTD win in the Florida enduro.
"We have the ingredients to win the race," he said. "The team is really motivated. It is really a shame what happened yesterday but we sat together, everybody including mechanics, driver and crews and we were really positive.
"We are ready for the race but with a little bit less practice than everyone else.
"Not everyone is showing their potential but Mercedes is looking strong and we are also pretty good. I think package-wise we are strong."
