PHILADELPHIA - What initially was described as a "mild concussion" for Jason Bay is becoming a more serious concern for the Mets, who were told Thursday that the leftfielder is not yet "symptom-free."

Bay first experienced headaches on the cross-country flight home after the July 25 game in Los Angeles, but he was not put on the disabled list until five days later.

He is eligible to come off the disabled list on Tuesday, but that no longer seems to be a possibility. He could be sidelined for up to another two weeks.

The Mets learned from Ryan Church in 2008 that treating concussions can be an inexact science and that it is better to be safe than sorry. Knowing that, they will wait a considerable period after Bay finally is free of the concussion symptoms before allowing him to play again.

With Church, the Mets examined him closely during a rehab stint before clearing his return to the field.

As for the prognosis on Bay, who has remained in New York, all the Mets can do is check on him periodically.

"That's in the hands of our doctors," general manager Omar Minaya said, "and each case is different.''

Pitching puzzle

The Mets have not yet announced their probable starting pitchers for next week's Rockies series at Citi Field, and manager Jerry Manuel said Friday that he still was going over the options.

With Monday's off day, the easiest course of action would be to again skip Hisanori Takahashi, who might not get another chance to start until next Saturday, when the Phillies visit Flushing.

Though it seems unlikely, Mike Pelfrey could be skipped after his recent string of disappointing starts, and Manuel did not rule it out when asked.

"Sure," he said. "It's always a possibility."

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