How can you tell when an injured, declining, or mechanically discombobulated pitcher is about to break out of whatever miasma of pain and confusion that has held him back and rediscover the stuff of his vintage years? The Yankees think they know, because following Tuesday’s rainout, they’ve elected to skip Shawn Chacon’s turn in favor of the eternal project Jaret Wright.

By the time this column sees print, the outcome of Wright’s start will be known. What won’t be apparent until Saturday is how Chacon’s confidence and stuff will respond to his being passed over. In Chacon’s last two starts, he pitched 13.1 innings, allowed eight hits, two runs, walked five, and struck out six. With Randy Johnson and Chien-Ming Wang pitching eratically at best, the Yankees can’t afford to scoff at Chacon.

Nor can they take too much time chasing after that elusive soap bubble known as Wright, who will be to the Brian Cashman administration what Steve Kemp and Ed Whitson were to his predecessors. The problem with Wright is that getting him to return to what he was is a quixotic endeavor, because he never truly arrived.

As a 22-year-old with terrific stuff, Wright was just league average. Arm troubles set in before he was able to demonstrate he could learn and grow on the job. Six years later, he fell into the hands of the Atlanta Braves. There, Wright benefited from a rare confluence of events: the right coach, the right park, the right league, and a fleeting moment in which his arm was quiescent and could endure the unnatural activity we call pitching. That was when the Yankees jumped on the soap bubble with both feet.

The Yankees have other options – Aaron Small now, Carl Pavano later, and, perhaps later still, Phil Hughes, recently promoted to Double-A. Of course, options don’t necessarily equate to answers, and if the Yankees are to stabilize their rotation before long, they’re going to have to make these evaluations with more aggressiveness than Joe Torre is used to. It’s not certain that April’s inconsistencies will extend to the season as a whole, but Johnson’s age and Wang’s inexperience and lack of a strikeout pitch suggest they might. There is also no telling when the league might catch on to Mike Mussina’s revised change-up.

For the Yankees, then, the fifth starter isn’t just a fifth starter – he’s one more guy who’s needed to provide a dependable performance. If there are no aces in the house, the load has to be spread across the whole rotation.

So last night’s start should signal both the beginning and the end of the search for Wright’s right stuff. Torre has stated that “Wright pitched well last time,” but that is an optimistic reading of what was another shaky start. Wright was charged with four runs in five innings, walked four, and did not strike out a Blue Jay – far from a dominant performance.

A better word for Wright’s last start would be “lucky.” A pitcher who puts 10 runners on in five innings and strikes out none should, by all rights, be barbequed by the opposition. There are, however, rare nights when balls that would normally find holes find fielders instead. Like most kinds of good luck, the kind that helps pitchers out on balls in play is generally fleeting.

Wright might also have been helped by the predominant right-handedness of the lineup the Blue Jays deployed against him. This season, lefties are batting an even .500 against Wright, while righties are “only” hitting .333. This is probably only a small-sample illusion; last season it was righties who battered Wright while lefties merely pounded him. When you’re talking about Jaret Wright, you have to make fine distinctions like these.

What’s the short answer to how you can tell when a pitcher is going to get better? When he pitches well and you don’t have to make excuses for his performance. In truth, it doesn’t happen very often, and even good starts can be misleading. Dwight Gooden pitched a no-hitter in 1996, but that didn’t make it 1985 again. Roy Halladay’s mechanics blew up in 2000 and he had to be sent back the minors and essentially reeducated, but he was 23 and the surgeons hadn’t yet gotten to him.

Tom Glavine was a knockabout pitcher for about a year, from All-Star break 2004 to All-Star break 2005,before righting himself, But he’s an unusual case – a future Hall of Famer with a veterans’ knowledge and inventiveness. The same is true of Greg Maddux, just an average pitcher with the Cubs last year, now 5-0 with a 1.35 ERA.

Glavine and Maddux were fighting the problems of age, of declining stuff. They weren’t trying to heal incisions that had been made in their arms, trying to find velocity after countless surgeries. Jaret Wright is, and that means not just relearning how to pitch, but doing it with a different set of mechanical tools than he employed just last year.

Were the Yankees the Devil Rays, you might say Wright would be a worthwhile project. After all, they’re not going anywhere, so they can endure the losses that come with experimenting with damaged goods. If the Yankees take too long with Wright, they may find themselves a pitcher, but at the cost of that bigger thing they were looking for – the pennant.

Mr. Goldman writes the Pinstriped Bible for www.yesnetwork.com.