The Lakers announced after the game that an X-ray on the ankle was negative, but Bryant is being listed as "out indefinitely" with a severe left ankle sprain, according to the Los Angeles Times.
With the Hawks leading 94-92 and 15 seconds remaining in regulation, Bryant worked one-on-one against Dahntay Jones on the right wing. As the clock hit five seconds, Bryant dribbled to the baseline and pulled up for a fadeaway jumper. The shot rimmed off, and Bryant's left foot landed on Jones' right foot, as the Hawks guard closely contested the potential game-tying shot.
Bryant tweeted that Jones should have been called for a foul on the play for sliding underneath him after the shot attempt.
"Dangerous play that should have been called," he wrote. "Period."
Jones disputed that assessment on his Twitter account.
"Tape doesn't lie," he wrote. "Ankle was turned on the floor after the leg kick out that knocked him off balance. I would never try to hurt the man. ... Leg kick that makes contact with a defensive player is an [offensive] foul. Period. The NBA changed that rule [two years] ago. Stop it!"
Replays showed Bryant's ankle roll over, and he initially remained motionless on the court as the clock stopped with 2.6 seconds remaining. Bryant eventually walked off under his own power after being attended to by trainer Gary Vitti. Yahoo! Sports reported that Bryant called the injury his "worst sprain since 2000."
The Lakers next play on Friday when they travel to Indiana to face the Pacers. Los Angeles dropped to 34-32 with the loss but remained a half-game up on Utah for the Western Conference's No. 8 seed after the Jazz loss to the Thunder on Wednesday.
Bryant finished with a game-high 31 points (on 11-for-33 shooting), seven rebounds and five assists. He has played in all 66 games for the Lakers so far this season.