"I feel great," Davis said Sunday morning. "And I don't have any symptoms of it. I'm not coughing. I'm not throwing up blood. I'm not doing anything. It's not even hard to breathe. The doctor said I could play -- and just don't get really, really fatigued. So that's what we're doing. And if I get really tired, I kind of just step to the side and take a break."
Doctors decided to send Davis to New York for additional tests after reviewing an X-ray of his lungs during a routine camp physical. However, Davis says that subsequent blood work didn't positively identify the disease.
Doctors told Davis his blood tests did not positively identify valley fever because he has either unknowingly had the disease for a while and it mostly has worked itself out of his system, or because the disease has yet to fully manifest itself.
Asked how long it may be in his system before running its course, Davis said: "It's person by person. A year, maybe. But another thing is, if you look at it, like 40 percent of people that live in Arizona get it in their life. It doesn't affect a lot of people that get it. So hopefully I'm one of those guys."
Davis, who spends his offseasons in Phoenix, suspects he may have contracted the disease while rehabbing a season-ending left-ankle injury in his native Arizona last summer.
Valley fever is a fungal infection found in desert regions of the Southwest. The fungus is released from the soil and inhaled.
"There were some dust storms during the summer when I was back in Arizona," said Davis, whose 2011 season ended with a collision with David Wright at Colorado on May 10. "I guess a lot of people have had complications from that."
Former Diamondbacks outfielder Conor Jackson suffered from a severe case of valley fever in 2009 while with Arizona and lost nearly a full year to the disease. Jackson described the symptoms at the time to the Arizona Republic as "mono on steroids."
Davis said he knows but has not spoken with Jackson about his serious bout with valley fever.
"Extreme cases, I could imagine, it would be tough," Davis said. "But I don't think I have an extreme case. I feel great now, obviously. If it gets really bad, you guys will find out, because I won't be playing. But I feel great now, and I don't see anything in the future. There's nothing that's come up. Once again, I could have had it for six months and not even known it. I can't answer a lot of questions of the future. As of right now, I'll be playing."
Mets general manager Sandy Alderson downplayed the relevance of Jackson's severe case.
"I've seen one player's case referred to," he said. "These things vary dramatically. ... (Davis is) not under any real restrictions. This is something that will resolve itself. ... And what I understand is that quite often there are no real significant issues with this in many cases. And when there are, it usually has to do with a compromised immune system or something else that's going on with the 'patient.'
"From our standpoint, he's continuing to do all the drills. He does have to avoid becoming exhausted. But we're going to follow up with it in New York [in April] when we get back."
Davis insisted he largely is unconcerned.
"If I had a cough, if I felt sick, I'd have maybe worries or something like that," he said. "But I feel great. It's kind of weird."
Adam Rubin covers the Mets for ESPNNewYork.com.