By Sean McAdam
CSNNE.com Red Sox InsiderFollow @sean_mcadam
BOSTON -- In 2006, his first full season in the big leagues, Conor Jackson hit 15 home runs, a figure he matched a year later, in 2007.
Since then, however, the newest member of the Red Sox, obtained minutes before midnight Wednesday, has hit a total of 21 homers over the last four seasons, covering more than 1,500 at-bats.
Even as a highly-rated prospect, Jackson was never projected as a true power threat and was instead viewed as more of a line-drive, gap-to-gap hitter. But still, the dropoff was stark.
It's possible the drop could be attributed to reduced playing time or a move away from homer-friendly Chase Field in Phoenix.
Or, it's possible, as some in baseball believe, that Jackson's numbers dipped after he contracted Valley Fever, a viral infection which usually targets residents of the Southwest.
Coccidioidomycosis, as it's officially known, takes the form of a mold spore. Inhaling the particles can result in flu-like symptoms and a general weakening of the body, resulting in lethargy, often for long periods of time.
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"I can't say that I've lost power or lost strength," said Jackson. "I feel stronger, or just as strong as I did in 2008."
Jackson first felt ill in the first week or so of 2008, but it took five or six weeks to properly diagnose the condition.
"It's like (having) mono -- on steroids," said Jackson with a chuckle. "I felt tired, really fatigued . . . I lost weight, lost my appetite.
"A lot of people get it and shrug it off, like it's a cold. Some people might get it and their immune system might find something else and it kind of metastasizes and spreads."
As the condition went undiagnosed, Jackson naturally found the downturn in his health "concerning. At first, I just wasn't playing well, but I thought it (was the result) of stress because I wasn't hitting that well. I was sleeping a lot, 14-15 hours a day.
"It finally got to the point where we had to figure out what it was. The longer you wait, the worse it gets. I think we caught in a timely fashion."
When told of the diagnosis, Jackson didn't know what it was, much less the consequences.
"Snowboarders get it and they come back to the East Coast and doctors there don't know what it is," said Jackson. "It's definitely something that's indigenous to the desert area."
While some severe cases require ongoing treatment and lifelong use of medication, Jackson's case wasn't deemed that serious.
The trade to the Red Sox, completed late Wednesday night, caught him by surprise. But he was happy to learn of the deal.
"It's exciting," he said. "I'm coming from a team that's 15 games out to a team that's in the middle of a pennant race, and playing in the A.L. East and probably one of the friendliest fan parks in the game."
Jackson can play first base and both corner outfield spots and is eager to contribute.
"Whatever they need," he said. "It's probably going to be a bat off the bench and here and there playing against left-handers. Whatever my goal's going to be or whatever my role is going to be, I'm going to be ready for it and be prepared."
Jackson was hitting just .249 with Oakland and is hitless in his last 21 at-bats.
"It's definitely been a down year for me statistically," he said. " But I've helped my stock a little bit by playing multiple positions, playing left, and playing right, playing third a little bit, playing first. Hopefully I'll get some ABs and impress some people here."
Sean McAdam can be reached at smcadam@comcastsportsnet.com. Follow Sean on Twitter at http:twitter.comsean_mcadam.