One of the surprise heroes of the team's World Series win in 2010, Huff has been affected by an anxiety disorder.
In a statement, he said: "Sometimes you have to pull back and work on things in private. This is one of those times."
What he's coping with is much more common than many people realize.
"Anxiety in one form or another walks through my door every day," said Leslie Davenport, a psychotherapist at the Institute for Health and Healing at California Pacific Medical Center.
Dr. Mason Turner is the chief of psychiatry at Kaiser Permanente San Francisco. "Anxiety disorders are very, very common and there's no reason to think they're not as common in athletes as they are in others," he said.
Both Turner and Davenport say more people of all ages are coming to see them with symptoms of anxiety or worry. Patients range from young kids with school issues to seniors thinking about what they could have done to business people finding it difficult to cope. The economy and fast pace of life all contribute, they say.
Treatment of anxiety disorders runs the gamut from meditation practices to medication management and psychotherapy, according to Turner.
Davenport believes in turning to natural methods like visualization and breathing to turn around issues. "One of the things that happens with anxiety is we shorten our breath, we hold our breath," she said.
There are simple tools that those affected by anxiety can learn, like taking in a full breath with awareness, exhaling fully and relaxing their body and mind, she said.
Huff is not the first athlete to deal with anxiety and its effects. Other athletes have gone through situations that sidelined them. One is Steve Blass, the former Pirates pitcher who won the 1971 World Series, then lost control after the 1972 season.
For athletes there has been a stigma attached to anxiety. But when someone high profile admits it, it can mean changes.
"It really does help others who are suffering from the same disorder to come out and say, 'if he can do it, so can I,'" Turner said. He said there isn't really a cure for anxiety, but if people face it head on, they can probably learn ways to control it.