The fifth-year guard also missed a pair of games at the end of November with an ankle injury.
Harris left Monday's game against the Toronto Raptors in the first quarter. The 24-year-old was playing just his second game after the ankle injury.
"The one thing I feel awful about is Gary Harris," Nuggets coach Mike Malone said, according to ESPN.com's Tim Bontemps. "Definitely keep Gary in our thoughts.
"He's frustrated, just getting back from an injury, and to have that [and] not be able to come back in [Monday night]. We'll see how severe the injury is, and hopefully we can get him back really soon."
Harris is averaging 16.6 points, 3.2 rebounds and 2.9 assists per game this season.
"Gary's such a big part of what we're trying to do," Malone added, per Bontemps. "Big loss."
Malone later noted, per The Athletic's Nick Kosmider, that he will fill Harris' spot in the lineup based on matchups and that Malik Beasley and Torrey Craig will play increased minutes. Craig has started all four times when Harris has been out of the lineup.