Nuggets forward Juan Hernangomez has been diagnosed with mononucleosis the team announced.
The Nuggets said his return will be determined at a later time but the Denver Post reported he is expected to miss four to six weeks.
Hernangomez, 22, has appeared in two games this season but has not scored a point in just 13 total minutes of playing time.
Nuggets coach Michael Malone noted to reporters last week that Hernangomez "doesn't have that same energy and zap that he had last year."
The 6-foot-9 Hernangomez averaged 4.9 points and 3.0 assists in 62 games as a rookie last season. He showed promise in the nine contests that he started last season, averaging 11.3 points and 6.1 rebounds in those games.