This Feb. 25, 2010, file photo shows New York Mets...

This Feb. 25, 2010, file photo shows New York Mets shortstop Jose Reyes during spring training in Port St. Lucie, Fla. Reyes is flying to New York for tests after doctors in Florida discovered a thyroid imbalance. The team said Friday, march 5, 2010, that Reyes will undergo further tests on Monday, and it could take up to 48 after for doctors to receive the results. (AP Photo/Jeff Roberson, File) Credit: Photo by AP

PORT ST. LUCIE, Fla. - With Opening Day in jeopardy for Jose Reyes, the Mets no longer can pretend that 2009 was only a bad dream. Dealing with their star players' freakish injuries and ailments is more like a recurring nightmare that now threatens to derail this season even before it begins.

The Mets were blindsided Thursday when the final round of tests on Reyes revealed a hyperthyroid condition that his agent, Peter Greenberg, said will prohibit him from any physical activity for two to eight weeks.

Despite the initial optimism shown by the Mets and Reyes' agents, general manager Omar Minaya was forced to admit on a conference call that the shortstop is very likely to join Carlos Beltran on the disabled list to start the season.

"I don't want to say that yet," Minaya said. "The reality is it doesn't look good. I don't want to say right now that he's not . But with that timeline, we have to prepare for that."

But shortly after yesterday's 8-2 loss to the Red Sox, Minaya made adjustments to that timeline, telling reporters in the clubhouse that the clock on Reyes began as soon as he was shut down last Friday. By Minaya's estimate, Reyes already is a week in, and the GM hopes next week's follow-up test will reveal that his thyroid levels have decreased.

Either way, hearing that Reyes - the shortstop and presumably the No. 3 hitter - will be home resting for the immediate future was another difficult blow to absorb.

"We just hope it's sooner rather than later," Jeff Francoeur said. "It would -- if it was eight weeks. That's going to be tough. You can get by with a week or two. But eight weeks? You're looking into May, and that's not good for us."

Minaya said the Mets will turn to Alex Cora, the $2-million backup, and possibly Ruben Tejada, the 20-year-old rookie who played for Double-A Binghamton last season.

Since Reyes was sent back to New York a week ago, Tejada has logged most of the playing time at shortstop. Cora had surgery on both thumbs last year but believes he is capable of handling the additional workload until Reyes is healthy again.

"I gotta be honest, I'm not Jose Reyes," Cora said. "But if it's the worst-case scenario, whatever that is, it's early enough that we can plan for it."

Only a day earlier, the Mets hoped Reyes would return quickly because initial tests on his thyroid were encouraging. On yesterday's conference call, Greenberg said Reyes even was given permission to work out Monday and Tuesday because the original diagnosis was "very, very mild." That's why yesterday's revelation took everyone by surprise - especially Reyes.

"He is very disappointed because the initial results said that he could possibly be back in a matter of days," Greenberg said. "I think all the results weren't in yet. speaking a little too soon, unfortunately."

Greenberg still described the prognosis as "good news" because Reyes will not require medication to control his overactive thyroid. It is expected to calm down on its own with rest and alterations to his diet - no seafood because of its high iodine content.

Reyes, who will remain at home in New York, is limited to nothing more strenuous than walking around or shopping.

"He can't raise his heart rate," Greenberg said. "They don't want him exercising or anything. And as long as he follows the diet, then they have no doubt that the thyroid will return to normal. They said that almost never is there a recurrence in this type of a case."

Reyes will be tested weekly, starting next week, to monitor his thyroid levels. When the doctors believe they have dropped to safe levels, Reyes will be cleared to resume baseball activities. Depending on how long that takes, he is likely to need another two weeks, at least, to get back into a game.

"There's still almost a month to go before Opening Day, so there's nothing but optimism and positivity in the clubhouse," David Wright said. "We're worried about Jose as a person - we want him to get healthy. Obviously, we want him on the field, but we're not going to sit here and hang our heads and feel sorry for ourselves."