Knicks Coach Tom Thibodeau has long been known as resistant to change, particularly in the way he uses his starters. He’s often been criticized for playing them for too many minutes, rain or shine, whether or not they are performing well.

So it was surprising this week, a quarter of a way through the season, when Thibodeau said that he was pulling the plug on Kemba Walker as the starting point guard in favor of Alec Burks, a reserve for most of his career and not a traditional point guard. And it wasn’t just that Walker, a four-time All-Star who signed with the Knicks in the summer, was being yanked from the lineup. Thibodeau told reporters that Walker would be out of the rotation entirely.

Changing a starter this early in the season is significant, particularly when it’s one with Walker’s résumé. At 31, Walker, in theory, should still be in his athletic prime.

But Thibodeau was trying to correct for an urgent, and frequent, problem: Knicks starters putting the team in a hole that the bench has to dig it out of. If playoff teams are consistently hurt by any part of their roster, it’s usually a thin bench. But for the Knicks, the starters — even beyond Walker — are the reason they are a fringe playoff team instead of near the top of the Eastern Conference standings.

Tuesday night’s game against the Nets was illustrative. Down 1 point at halftime, the Nets came out of the break with a blistering 14-0 run against the Knicks’ starters minus guard RJ Barrett, who missed the second half with an unspecified illness. The starters climbed back into the game and briefly took the lead. But the Knicks lost the 112-110 thriller in Brooklyn — in part because coming out of halftime flat left the team playing the Nets (15-6) from behind for most of the second half.

This wasn’t an exception. In a Nov. 10 loss to the Milwaukee Bucks, the reigning champions, the Knicks went down double digits in the first quarter. Even against the Houston Rockets, one of the worst teams in the N.B.A., the Knicks fell behind 18-11 in the first quarter before tying the game by halftime and winning. The next night, Nov. 21, against Chicago, the Bulls raced out to a 20-8 start en route to victory.

The starting lineup the Knicks (11-10) have played for much of the season — Walker, Barrett, Evan Fournier, Julius Randle and Mitchell Robinson — hasn’t just struggled. Its net rating — a measure of how much better or worse a team or group is than their opponents — is negative 15.7, according to the league’s tracking numbers. That places this unit among the worst starting or bench lineups in the N.B.A.

The evidence was becoming undeniable. Thibodeau needed to try something else.

Walker wasn’t the sole issue, but he was a big part of the problem. He’s averaging 11.7 points per game on 42.9 percent shooting from the field, and an excellent 41.3 percent from 3-point range. But Walker’s play took a nosedive in November after a hot start. In 12 games last month, Walker shot only 29.6 percent from deep. If his 3s aren’t falling, there isn’t much else he’s doing on the court.

Because of chronic knee issues in recent years, Walker has lost his explosive first step, so he’s not able to get to the rim as effectively. And because of his height — Walker is listed at 6 feet tall — and slower foot speed, Walker was targeted on defense. The only way to justify keeping him on the court would be if he spread the floor with his shooting, and he is no longer doing that.

Inserting Burks into the starting lineup for Walker makes some things easier for the Knicks. He’s bigger — listed at 6-foot-6 — which makes him a more versatile defender. On Tuesday night, he was just as likely to guard the 6-foot-5 James Harden as the quick rookie guard Cameron Thomas, who is 6-foot-3. Early in the third quarter, Burks blocked a Patty Mills 3-pointer — easier for him than for Walker.

“You’re able to switch 1 through 4,” Derrick Rose, the Knicks reserve guard, said of Burks’s insertion into the lineup. “You’re more versatile. I mean, A.B. is a hell of a player. A playmaker. A great shooter.”

But Burks doesn’t fully solve a starting lineup problem that led Thibodeau to increasingly rely on the bench late in games. The Knicks don’t have much of a fast-break offense and often depend on isolations to get their points — which would be fine if their shooters did more work on their own to get open rather than just standing still. The team is near the top of the league in contested shots and toward the bottom in wide-open ones.

Fournier’s stats dipped in November like Walker’s did, causing Thibodeau to barely use him in key moments late in games. Thibodeau did call his number on Tuesday night against the Nets, and Fournier rewarded him by hitting a game-tying 3-pointer with 18 seconds left. But overall, Fournier shot 5 for 12 for 13 points in 22 minutes, with no rebounds or assists. Like with Walker, if Fournier isn’t consistently a 3-point threat, there’s little reason for him to be on the floor.

Randle, the team’s best player, has faced an onslaught of double teams without reliable shooting around him, and he has struggled. Randle is shooting only 41.7 percent from the field and 32.5 percent from 3 — all below his career averages. All of Barrett’s numbers have declined from last year as well. Barrett has improved his finishing around the rim, but his shooting has always been his biggest question mark, one he appeared to answer last year when he shot 40.1 percent from deep. Now he’s at 32.1 percent. (For his part, Barrett also started slowly last year, only to pick it up in the second half of the season.)

Thibodeau was not in the mood to discuss the lineup change after Tuesday’s loss. Asked about it, Thibodeau expressed anger at the game’s officiating and then left the news conference after just one question.

The saving grace for the Knicks has been their bench trio of Rose, Obi Toppin and Immanuel Quickley. The team is third in the N.B.A. in bench scoring. Toppin is a sorely needed threat at the rim and in transition and does something the Knicks generally don’t do well: cut. Quickley and Rose have provided quality shooting, especially late in games, and Rose has been one of the few Knicks effective at getting to the rim.

Swapping Walker for Burks swap has already paid dividends. He scored 25 and 23 points in the last two games, his only two starts of the season. And the Knicks may need to make more adjustments. More lineup changes mean the increased potential for hurt feelings among veteran players, but as Thibodeau said before the game on Tuesday: “You have to put winning first.”