The news comes as the Brooklyn Nets (14-6) host the Knicks (11-9) on Tuesday night.
“We’re going to make a change,” Thibodeau told reporters on Monday afternoon. “Alec (Burks) is going to be the starter.”
Thibodeau explained how Burks’ size at 6-foot-6 is preferable to Walker’s at 6-foot.
“I just don’t like the way we’ve been trending, the inconsistency of our team and we’re going to try to make a change,” Thibodeau said. “I want to get bigger, I want our defense to be more intact, so basically that was it.
“We got to do something different.”
The Knicks’ defensive rating of 108.0 ranks 16th in the NBA.
Through 20 games, the Knicks allow 106.2 points per game, which ranks 14th in the NBA.
Walker, 31, signed a two-year, $20 million deal in the summer with the Knicks.
It came after the Oklahoma City Thunder bought Walker out following a trade from the Boston Celtics.
The four-time All-Star guard is averaging career lows in points (11.7), rebounds (2.6), assists (3.1), field goal attempts per game (9.8), and minutes (24.5).
Walker started the season shooting 50 percent in six games in October, averaging 15 points per game.
“Cardiac Kemba” has since cooled off.
Through 12 games in November, the former UConn star is averaging 10 points on 39 percent shooting and 29 percent from 3-point range.
Advanced stats show the Knicks have struggled defensively with Walker on the floor.
Opposing teams have outscored the Knicks by 15.7 points per 100 possessions in those minutes.
The Knicks’ defense rating of 118.9 with those five players on the floor is among the worst in the NBA.
“We’ve got small guards, and so when you add (Burks) to the mix, it gives us size at that position and it allows us do some different things that I thought were beneficial to the group, so the big this is, is getting bigger,” Thibodeau said. “At times, we’ve played very good defense and other times we haven’t, and we’ve just been inconsistent.”
During Saturday night’s 99-90 win against the Atlanta Hawks, Burks scored 23 points in 39 minutes played.
In the 2021-22 season, Burks is averaging 10.5 points per game in 22.3 minutes.
“It’s a tough decision to make, but you always have to do what you think is best for the team,” Thibodeau said. “I view Kemba as a starter, and so it’d be tough to play three small guards together.
“I gave it consideration, and I’ve got great respect for who Kemba is as a person… and all that he’s accomplished in this league.”
Walker did not play against the Hawks on Saturday.
On Friday, Walker scored 17 points in 23 minutes played in a 118-97 loss to the Phoenix Suns.
“The difficult part is who Kemba is,” Thibodeau said. “He’s a top-of-the-line guy, great character and he’s had heck of a career.”
Rose didn’t play Saturday due to a sprained ankle.
Thibodeau said Rose is questionable for Tuesday’s game.