PHILADELPHIA - Fans would like to believe that players can will themselves to greatness, particularly those infused with that most intangible quality: grit. There is no way to measure grit, but we know it when we see it, or at least we think we do.

Jimmy Rollins is gritty. So are Jorge Posada and Shane Victorino and Brett Gardner. And so, of course, is Andy Pettitte, the Yankees' first choice to start Game 6 of the World Series on Wednesday at Yankee Stadium.

Sometimes the grittiest players, the ones renowned for playing the right way and coming through at big moments, do not deliver. Derek Jeter came up as the potential tying run in the ninth inning of Game 5 on Monday, with a moonlighting closer, Ryan Madson, teetering on disaster for the Philadelphia Phillies. Madson threw a sinking fastball and Jeter grounded into a double play.

Watching from the bench, Pettitte might have sighed. When Mark Teixeira fanned for the final out, it meant more work for Pettitte in a season that seemed to reach the point of exhaustion on Saturday.

"It was tough," Pettitte said that night, after beating the Phillies with six workmanlike innings. "I'm not going to lie to you. I couldn't put the ball where I wanted to, I wasn't getting it down and away consistently like I wanted to, and I wasn't able to throw my curveball for strikes. It was an absolute grind tonight, that's for sure."

The victory improved Pettitte's career postseason record to 17-9, but he said he could not remember any of those victories being as much of a struggle as Game 3. Now, if he tells manager Joe Girardi he feels fine - and it is hard to imagine him saying otherwise - Pettitte will try to win again on three days' rest, with a championship at stake.

It will not be easy. A.J. Burnett pitched on short rest in Game 5, also with the title in sight, after a dominant performance in Game 2. Yet Burnett had nothing - no curveball, no fastball command, no chance. Girardi said there was no correlation to the short rest and the poor performance, but what else could he say?

At this point, Girardi has no other options. Joba Chamberlain was the fourth starter in the regular season, but he faded down the stretch as his innings limit approached, and now he is a short reliever again.

The Yankees' other starters were Sergio Mitre, an erratic right-hander who is not on the World Series roster, and Chad Gaudin, who has pitched one inning in a month. Chien-Ming Wang, the nominal No. 2 starter when the season began, is out until May after shoulder surgery.

There was a time when teams would regularly line up three starters and survive the postseason, as the Yankees are trying to do. From 1986 to 1991, the World Series champion never used more than three starters. Since then, every champion has used four.

Pettitte, 37, has not made starts four days apart since the end of the 2006 season, when he pitched for the Houston Astros. According to the Elias Sports Bureau, he is 2-6 with a 4.70 earned run average pitching on three days' rest for his career in the regular season, and 3-1 with a 3.24 ERA in the playoffs. But there is no recent data to analyze.

There are past highlights of strong World Series starts on three days' rest. In Game 5 of the 1996 World Series, Pettitte earned Joe Torre's everlasting trust by working eight and a third shutout innings in Atlanta to beat the Braves, 1-0. In 2003, he allowed no earned runs over eight and two-thirds innings in a Game 2 triumph over Florida.

Those games, though, may have nothing to do with the Pettitte of 2009. Pettitte, more than anybody, understands this, as he explained after Game 3: "It's hard to draw on past success or whatever when you're standing out on that mound and the ball is not going where you want it to."

The Yankees know they can count on Pettitte's competitive will. If there is a way out of trouble, they know he will find it. But if his pitches are as lifeless as Burnett's were in Game 5, there may be nothing he can do, no magic to summon. And his teammates must score against Pedro Martinez, who has not pitched since Game 2 and rested the first half of the season.

"We're always confident with Andy pitching," Jeter said. "He's been in a lot of big games for us. He's come through for us. But we all have a job to do."

Pettitte could close out the Phillies the way he silenced the Angels. But even if he falters, the Yankees have C.C. Sabathia for Game 7. Sabathia will be on short rest, too, but he has shown twice this postseason that he is essentially the same pitcher on three days' rest as he is on four.

The Phillies' Game 7 plans are unclear, but manager Charlie Manuel has used five different starters this postseason, so he will have more choices. Manuel could even call for Cliff Lee on two days' rest because Thursday would be his day to throw in the bullpen.

Asked for his thoughts after winning on Monday, Lee gave the earnest answer almost all pitchers give this time of year.

"I'll pitch whenever they want me to pitch," Lee said. "That's about as clear as I can say it."