The team announced the change in the injury report on Sunday evening, but don't read too much into it. Williamson is still expected to make his NBA debut on Wednesday night against the San Antonio Spurs.
The upgrade for Williamson, who has been listed as out for every game this season after having knee surgery the day before the regular season started, is a necessary step in his recovery process.
The NBA encourages teams to gradually improve a player's status coming back from injuries so that a player doesn't jump from out to available.
Pelicans executive vice president of basketball operations David Griffin told reporters last week that Williamson's expected debut will be against the Spurs.
The long-anticipated debut will tip off at 9:30 ET on ESPN.
Williamson, the No. 1 overall pick in the 2019 draft, averaged 23.3 points in the preseason while shooting 71.4 percent from the field.
His original six-to-eight-week timeline for recovery from meniscus surgery has stretched out to 13 weeks. The Pelicans have taken their time with his recovery process and have been adamant that they weren't going to rush him back onto the court.
Williamson joined a handful of other Pelicans on the injury report for Monday. JJ Redick is listed as probable, while Jrue Holiday, Derrick Favors and Jahlil Okafor are all listed as questionable. Kenrich Williams (back) and Darius Miller (Achilles) are listed as out.