Randy Moss Stepping Away From ESPN Gig Over 'Personal Health Challenge'

Randy Moss is stepping away from his role on "Sunday NFL Countdown" ... to focus on his battle with an undisclosed health issue.

ESPN announced the move Friday morning ... explaining the Hall of Famer will be gone for "an extended time" as he continues to deal with "a personal health challenge."

Moss first made his fans aware of his medical ailment on Dec. 1 ... though he kept things vague, saying merely he's "battling something internal."

Moss revealed he would need to wear sunglasses on ESPN's set while dealing with the matter. He also asked "all the prayer warriors to put their blessed hands on me and my family through these hard times."

ESPN said it will give Moss all the time he needs to get better -- writing in a statement, "He has ESPN's full support, and we look forward to welcoming him back when he is ready."

Moss has been a mainstay on the network for years after retiring from the NFL -- and even ESPN called him Friday "an invaluable member of the team" who is "consistently elevating Countdown with his insight and passion."