CHICAGO – Pedro Martinez’ health continues to be a shaky issue.

Martinez is suffering from what’s believed to be food poisoning, and his condition caused him to spend a few hours in Northwestern Hospital on Friday night. The Met ace was accompanied by trainer Ray Ramirez but did not need to stay overnight.

“He did go down there … and what he did was, he got an IV to replace some fluids, and they did a CT scan just to check, just to see if it was an appendix,” GM Omar Minaya said yesterday before the game. “And everything’s clear and everything was fine.”

After the game, Martinez said, “I had a couple of irritated muscles in my stomach, I guess from vomiting. But everything is fine. All the tests came out OK. Blood tests, all of them were fine.”

Martinez also said he was able to do some long-tossing before the game, though he said, “It felt really weak. The doctor told me that I should wait at least two or three days to actually get going on doing something, but I felt better [yesterday]. So I took myself out a little bit to play catch at least and continue to feel the ball until I get my strength back.”

Martinez, who is still on the DL with an inflamed right hip, also talked to reporters on Friday, and he was clearly weak. He said that day he had already lost three pounds, and he admitted he had barely been eating.

Yesterday he said, “I don’t have the strength to get on the mound yet. But I’m pretty sure I’ll get it soon. I just need to start eating and thats hard to do for me.”

Meanwhile, the food poisoning has curbed Martinez’ comeback from the hip problem. He was slated to pitch Wednesday in Cincinnati, but manager Willie Randolph said yesterday that Steve Trachsel will go instead.

The positive of Martinez’ problem (which he believed was chicken-caused) is that this will provide even more time for his hip to recuperate.

“It could be a blessing in disguise, but to me, it’s not really because you still want him to be out there on the mound and keeping his regular routine,” Randolph said.