Ronnie Coleman's family is providing an update on his health condition -- revealing the legendary bodybuilder is suffering from an infection in his bloodstream ... and has been moved to a specialized medical center for treatment.

The news was released on Tuesday ... a day after Coleman's loved ones told fans he was hospitalized with a "serious medical condition".

The family said Coleman was moved to the new facility to receive the "highest care possible," and he "remains under intensive medical supervision."

"While his condition remains complex, there have been encouraging signs of progress, and his medical team is working around the clock to support his recovery," the statement read.

"At this stage, key evaluations and treatments are ongoing, and Ronnie continues to fight with the strength and resilience that define him."

As the 61-year-old battles this medical emergency, his family asked fans to keep Coleman in their thoughts and prayers.

Colemam is considered one of the greatest bodybuilders of all time ... and shares the record for most Mr. Olympia titles (8) with Lee Haney.