Ronnie O'Sullivan has withdrawn from the Masters in January due to personal reasons.
The 44-year-old, who has won the event seven times, will be replaced by world number 17 Ali Carter.
The Masters features the top 16 players in the world rankings and takes place at London's Alexandra Palace from January 12 to 19.
A statement from World Snooker read: "Ronnie O'Sullivan has pulled out of next month's Dafabet Masters for personal reasons.
"The world's top 16 players qualify for the event. But O'Sullivan has decided not to take his place. The player ranked 17th, Ali Carter, will now qualify.
"The draw for the first round will be made on Sunday afternoon during the mid-session interval of the Betway UK Championship final."
O'Sullivan was beaten 10-4 by Judd Trump in the 2019 Masters final.