Carlos Alcaraz was forced to withdraw from the quarterfinals of the Paris Masters Friday.
On Saturday, he announced the extent of his injury, which will keep him out about six weeks.
“After my withdrawal yesterday and having been evaluated by my medical team … unfortunately this is the result of my injury: an internal oblique muscle tear in the left abdominal wall with an estimated recovery time of six weeks,” Alcaraz tweeted Saturday afternoon.
The injury will force Alcaraz to miss the ATP Finals and the Davis Cup.
“It is tough and painful for me to miss these two events, which are so important to me, but all I can do is be positive and focus on my recovery,” he said in a follow-up tweet.
The Australian Open begins Jan. 16. A six-week recovery timeline would have him ready before the new year, but it’s no guarantee.
Alcaraz is ranked No. 1 in the world at just 19 years of age, the youngest player to ever take the top spot.
He won his first two matches at the Paris Masters in straight sets but retired in the tiebreaker of the second set on Friday after losing the first.
He went 57-13 this year, winning the U.S. Open and making it to the quarterfinals of the French Open.