Lamar Odom is reportedly in desperate need of a kidney transplant.

According to a source close to Odom's current situation in the hospital, the 35-year-old former NBA star "definitely" needs a kidney transplant, Us Weekly reported.

Although Odom has been making a little progress every day, he's been dealing with major kidney failure and being on dialysis. However, an insider said his wife Khloe Kardashian and her family find Odom's brain injury "of the most concern" after he suffered a dozen strokes.

"That's the most serious thing he's dealing with," the insider told Us, adding that the full extent of damage to Odom's body has yet to be determined.

"He can say a few words," the source explained of Odom, who cannot speak in full sentences yet. "He's doing a tiny bit better, but he has a very long road back to full recovery -- if that."

Odom is being treated at Cedars-Sinai Hospital in Los Angeles for a drug overdose after being found unconscious October 13 in a Nevada brothel. He initially spent four days in a coma at Sunrise Hospital in Las Vegas before being transferred to his current location via helicopter.

"There are still a lot of tests that need to be done," the source noted.

"He'll get more of his motor skills back gradually, but cognitively, he's not where he used to be," said the insider.