SEATTLE -- Boston Red Sox slugger David Ortiz confirmed last night that he had indeed spent last Saturday night at Massachusetts General Hospital, held overnight for observation and treatment.

Ortiz said he was not feeling any chest pains, but that he was suffering from dehydration and stress, brought on, he said, by a lack of sleep, not to mention the daily pressure of playing baseball for the Red Sox.

He was taken to the hospital after Saturday's game by one of the Sox' team physicians, Larry Ronan. Tests showed his blood pressure was fine.

The intensity of Ortiz's stress level was raised last weekend when the Red Sox played their archrivals, the New York Yankees, in a five-game series, which the Yanks swept.

"It was like my whole body was cramping. I was just getting IVs and stuff," said Ortiz, trying to explain how he was feeling and what was done to him in the hospital.

"There was a lot of stress. I wasn't sleeping at all. I'd been having problems sleeping for four or five days, and there was what happened with those games against New York. That was a lot of stress going on. I stress about everything. I stress a lot sometimes. When you stress out, your whole body can change in a minute," said Ortiz yesterday before the Red Sox played the Seattle Mariners in the first game of a three-game series at Safeco Field.

Ortiz was released from the hospital Sunday and was back in the Red Sox' lineup for the game against the Yankees that night.

He said he started to feel ill Friday, during the "day" portion of the day-night doubleheader. Ortiz went 0-for-4 and was lifted for a pinch-hitter, Wily Mo Pena, with Boston trailing, 12-3, in the ninth.

He told reporters he needed to get some rest after Boston's 12-4 loss.

"After game one, I went home to take a nap. I was beat up. I couldn't sleep at all. I got up, took a shower and went back to the field (for the second game)," said Ortiz.

Ortiz, 30, went 2-for-5 in six plate appearances in the second game, with two runs scored and a pair of RBI, including a ninth-inning homer off the Yankees' ace closer, Mariano Rivera, in Boston's 14-11 loss.

That game ended at 12:52 Saturday morning, and at 1:20 Saturday afternoon, Ortiz was in the lineup for that game. He went 0-for-2 with a sacrifice fly and a run scored as the Yankees clobbered the Sox, 13-5. His last at-bat came in the seventh inning.

He told Ronan he wasn't feeling well around the eighth inning of the game.

"I wasn't feeling good Friday, but the next day it got worse," said Ortiz.

So Ronan arranged for Ortiz to go to the hospital for tests. After everyone had left the clubhouse, Ortiz was transported by car to the hospital. His family, naturally, was concerned, especially one of his daughters, when it was decided he should spend the night in the hospital.

But his condition improved enough to permit him to return to the Sox for the Sunday night game, and he has been in the lineup for every game since. Indeed, Ortiz had a pair of homers against the Angels in a three-game series that finished up Thursday night, boosting his major league-leading total to 46.

Ortiz's medical episode was quiet until it surfaced on a blog (carpundit.typepad.com) Thursday night and was confirmed by the Boston Herald.

Ortiz was reluctant to talk about it when asked after the Sox' game in Anaheim Thursday night. But yesterday he met with a handful of regular traveling media members to answer questions about the situation.

"I heard it was all over the place (in the media), that people were finding out about it," said Ortiz.

"People sometimes worry about my situation. I don't want to go back to Boston (with) people freaking out about this. I know when news comes out people want to get information. I just want to get it over with," said Ortiz.

He said he had even been getting some sleep lately.

"I'm feeling better (since) I came to the West Coast. There's plenty of time to sleep," said Ortiz, his trademark smile returning to his face.

He was happy that he didn't show any signs of having high blood-pressure.

"I'm a healthy son of a (gun)," said Ortiz.

Then he went out and joined his Red Sox teammates on the field for batting practice, wowing the fans with some titanic home runs that produced oohs and aahs all around Safeco Field.

skrasner@projo.com / (401) 277-7340