The movement on Halladay’s pitches can be seen in numbers compiled by the Inside Edge scouting service. Batters swung and missed at only 15 percent of his strikes, about the major league average. But they made solid contact only 7 percent of the time, one of the better rates in the league  the pitches looked good, but they flitted from the bat barrel at the last second.

Halladay’s 206 strikeouts last year, a career high, were all but unintentional.

“Really, I try and avoid them,” he said. “My main goal is to get ahead and get balls put in play early. It wasn’t something I tried to do. But if you get ahead in the count quickly and you have a chance to put guys away, you do it.”

The hits Halladay does allow do little damage. The Yankees’ Johnny Damon has rapped him worse than almost any hitter  a .338 career average  but conceded, “When I get the hits, it’s with nobody on base.” Sure enough, with 27 hits in 80 at-bats against Halladay, Damon has only two runs batted in, one on a solo home run.

It is almost unfathomable now, but when this decade began, Halladay was a failed major leaguer. He had been Toronto’s first-round draft pick out of his Colorado high school and reached the majors in 1998 with a bang  he came within one out of a no-hitter against Detroit in his second start  but he devolved just as fast, sticking with a conventional four-seam fastball with no deception and less success.

It all collapsed in 2000, when Halladay posted a 10.64 E.R.A. in 67 2/3 ghastly innings. (Learning that the worst E.R.A. for a pitcher throwing at least 50 innings belongs to the great Roy Halladay is like opening Mozart’s desk drawer and discovering the worst sonata in history.) He was sent back to the minor leagues the next spring, all but lost.

“I saw him in Pawtucket laboring, throwing 88 miles an hour tops, and searching for an out pitch and his command,” the Astros scout Paul Ricciarini said. “Anyone could have had him. Anyone could have had him for a body, basically.”

The Jays’ pitching guru, Mel Queen, rebuilt Halladay in the minors. Queen outlawed the four-seam fastball and lowered Halladay’s arm angle to generate more movement on a sinker and cutter. Halladay pitched well after his July 2001 return to Toronto. Over the next two seasons, he went 41-14 and won the Cy Young Award in 2003. He paid for throwing 266 innings that season with some shoulder problems the next year, but has been consistently outstanding ever since.