The league said that Garland, considered a "star player" under the player participation policy, was able to play in one of two games of the team's back-to-back on November 23 and 24.
"The violation occurred when the Cavaliers failed to make Garland available for the team's nationally-televised game on November 24 and instead made him available on November 23 which was not a nationally-televized game," the NBA said in a statement.
It is the second time this season that the Cavaliers have been fined for violating the player participation policy.
They were fined $100,000 for resting Donovan Mitchell and Evan Mobley for a November game against Miami.
The NBA adopted the player participation policy before the 2023-24 campaign to limit when teams benched uninjured players for rest during regular-season games in a bid to boost participation by star talent in major contests.