Michael Norris, LaBeouf's attorney, said in a statement Friday LaBeouf underwent four hours of surgery. His left arm remains immobilized from the elbow down.
"He will need regular medical supervision until his doctors clear him to return to work," Norris said in the statement. "His doctors remain hopeful that he will fully recover, but due to extensive surgery and the nature of the injuries, there remains a substantial risk of both infection and other complications."
Photos posted on entertainment blogs Friday showed the actor wearing jeans, a ballcap and a T-shirt missing one sleeve as he smoked a cigarette outside the Los Angeles hospital where he has been recovering since the surgery. Bandages and a brace cover his left arm, leaving only his pinkie finger exposed.
LaBeouf has been filming the "Transformers" sequel, "Revenge of the Fallen." Director Michael Bay said the injury may be added to the script.
"His two fingers are pretty smashed, but we're figuring out a way to shoot around it, kind of write it into the story," Bay told "Access Hollywood" in an interview airing Friday.
Bay claimed his leading man was not drunk at the time of the crash and insisted that "that's gonna go away."
"He was drinking hours and hours before," Bay told the syndicated entertainment show.
LaBeouf's passenger in the accident was Isabel Lucas, a 23-year-old Australian actress who appears in the "Transformers" sequel. She was not injured.
Sheriff's officials have said they won't release the other driver's name until the official investigation is completed and a report is issued, which could take weeks.
LaBeouf's attorney said the actor has cooperated with police and that independent investigators "received information that suggests that the other driver may have been traveling upwards of 50 miles per hour, and that said driver may not have been looking forward at the time of the accident."
"We are very appreciative, again, of the patience that everyone has shown us, and of the many concerned citizens who have stepped forward to provide information regarding this collision," the statement continued, adding that anyone with information about the accident was urged to call Norris directly.
LaBeouf has more than a dozen film credits, including last summer's blockbuster "Transformers," which grossed more than $700 million worldwide. Steven Spielberg was a producer on the first "Transformers" (and is again for the sequel), and he cast LaBeouf as Harrison Ford's son in "Indiana Jones and the Kingdom of the Crystal Skull" — a sought-after role in which LaBeouf evoked the look and attitude of a young Marlon Brando.
LaBeouf can next be seen in the thriller "Eagle Eye," due next month.