A week before the playoffs begin, the Yankees are worried about the health of another starting pitcher. This time, it’s Orlando Hernandez.

A tired right shoulder was going to prevent El Duque from making his scheduled start last night, but the game against the Minnesota Twins was postponed by rain. It will be made up as part of a doubleheader today at 4 p.m.

Now Hernandez, who had surgery on the shoulder in May 2003, is not expected to pitch again until at least Thursday or Friday. If he’s still ailing heading into the postseason, an already shaky Yankees rotation could be in big trouble.

“It’s always worrisome when your pitchers have trouble and you start the playoffs next week,” manager Joe Torre said. “Right now, we obviously take the healthiest people and the most qualified people.”

That makes for a short list. Javier Vazquez has struggled badly down the stretch, and 39-year-old Kevin Brown just missed three weeks after breaking his non-pitching hand when he punched a clubhouse wall on September 3.

Brown returned Sunday at Fenway Park and was tattooed by the rival Red Sox, giving up four runs and six hits in the first inning. He was chased after getting only two outs – now he might wind up in the bullpen when October rolls around.

Hernandez, believed to be 38, has been the Yankees’ best starter since July 11, when he came off the 60-day disabled list and was called up from Triple-A Columbus. He’s 8-1 with a 2.87 ERA in 14 starts.

And the Yankees surely figured they could count on him in October, too, when he’s been at his best in the past. The right-hander is 9-3 with a 2.51 ERA in 16 career postseason games.

Hernandez lost his last outing against Toronto and threw a season high 123 pitches, but Torre said he could have pitched yesterday if needed.

El Duque was agitated as he answered questions and insisted he wasn’t concerned about his shoulder.

“I think it’s normal in the recuperation of the arm, and in a couple of days I’ll be fine,” he said through a translator.

But when asked whether he would be starting if it were a playoff game, an agitated Hernandez replied: “I don’t know my future.”

Mike Mussina (12-9) will start the first game today against Twins ace Johan Santana (20-6) in a potential playoff preview. Jon Lieber (13-8) will go in Game 2 against Kyle Lohse (8-11).

The Yankees lead the Red Sox by 2 1 /2 games atop the A.L. East.

Also yesterday, Yankees pitcher Brad Halsey was suspended for three games and fined $1,000 for throwing up and in to Boston’s Dave Roberts on Sunday. Halsey appealed, so he remains eligible to pitch until his hearing. Even if his suspension is upheld, Halsey doesn’t expect it to take effect until next season.