Police said Jefferson was hit head-on by an impaired driver, 55-year-old Michael Dunn, and then hit by a third car in Mobile County, Alabama.
Dunn died at the scene.
Considered before the accident as a potential middle-round pick in the NFL draft on April 27-29 in Kansas City, Jefferson is expected to miss the 2023 season but could play in 2024.
Attorney Brad Sohn released a statement to ESPN on Wednesday on behalf of Jefferson and his family.
"A drunk driver tragically hit my client, Michael Jefferson, on Easter night," Sohn wrote. "Michael would not have made it this far without being a fighter and remains in good spirits under the circumstances.