Cleveland Cavaliers forward Larry Nance Jr. is reportedly dealing with a mysterious illness that has kept him tied to the bed and has caused rapid weight loss.

Nance has lost 20 pounds since contracting the illness on March 29, the Cleveland Plain-Dealer reported Wednesday. Every test he’s received has come back negative and it is not coronavirus, according to the newspaper.

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He was described as being "on the mend," but whatever has been plaguing him was undetermined.

The 28-year-old first-round pick of the Los Angeles Lakers in 2015 has played in 29 games for the Cavaliers this season. He also missed some time with a fractured hand.

Nance is averaging 10.1 points, 7.1 rebounds, 3.1 assists and nearly 2 steals per game this season. It is his third full season with the Cavaliers, who were looking to make some strides with a young corps in 2020-21.

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The Cavaliers are 18-32 and rank toward the bottom of the Eastern Conference. The team has gotten solid performances throughout the season from Collin Sexton, Darius Garland and Isaac Okoro and added Jarrett Allen through a big trade earlier in the season.

But without Nance and a few other guys, the team hasn’t been able to be at full strength.

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Nance is expected to miss Thursday’s game against the Oklahoma City Thunder as well.