It is the pitch that alters lives.
Josh Bard is gone because of the knuckleball. Doug Mirabelli is here because of the knuckleball. Plenty of batters have had their lives affected by the knuckleball.
''When I was with the Phillies, [manager] Danny Ozark would take the big-swinging guys like [Mike] Schmidt and [Greg] Luzinski out of the lineup," says Yankee third base coach Larry Bowa. ''Let some subs get the 0-fers."
That's baseballese for 0 for 4, 0 for 5, things like that. But that's not even the full effect. ''Someone's swing can get messed up for a week," Bowa adds.
But there cannot be a more graphic demonstration of one pitch's power than what we've seen unfolding over the past month. Catching Tim Wakefield has been an ongoing topic of conversation since spring training began.
Wakefield understands the fallout, and he is troubled by it.
''I feel horrible about what happened to Josh," he declares. ''I know how much effort Josh put into the job while he was here."
That's as far as he wishes to go, however. He can't bring himself to frame this in terms of his flutterball having complete power over someone else's life.
''I can't think that way," he says. ''I don't want to be the reason John Flaherty retired."
Ah, John Flaherty. Wasn't he in spring training for about two hours?
Yes, he was, and just this past week he said that while there were several factors involved in his decision to retire, it took only two days of attempting to catch Wakefield for him to decide that it would be better for his mental health if that job were handled by someone -- anyone -- else.
Being a backup catcher in Boston is a bit more specific a job than it is anywhere else in baseball. Elsewhere, a backup may spell the No. 1 guy on the basis of the lefty-righty thing. Not here. In Boston, someone other than Jason Varitek is going to catch Wakefield every fifth day. And if catching Wakefield were the alternative to a jail term, then many seasoned backstops would prefer two weeks of the 6 a.m. wakeups, the three squares, the little sink, the skinny mattress, and the charming roommate.
'Twas once said of Smoky Burgess that you could wake him up at 3 a.m. on Christmas Day and he could bang out a pinch hit. Now we know that you can fly Doug Mirabelli cross-country, have him change into his uniform in the back seat of a police vehicle, send him onto the field, and with just eight warmup pitches, have him catch a flawless seven innings for Tim Wakefield. So all's well that ends well, no?
Not quite. Wakefield is still bothered by the Bard situation.
''I don't think Josh really got a fair shake at becoming good at it," Wake says. ''He could have done it, but we just didn't have time to experiment.
''But I still feel horrible. He was a great teammate and a true professional, a pro's pro. He worked his tail off. He studied tapes of Doug catching me. He caught me every single day, not just in my 'sides' [i.e. side sessions between starts], but playing catch in the outfield every day. He would have gotten it.
''I'm just glad the Padres have told him he'll be staying with the big club. He did have options, but they told him he'll be staying. It could be a good situation. [Mike] Piazza may not be there for more than a year, and then he could be the No. 1 guy."
Does any other sport have anything comparable to the phenomenon of a personal knuckleball catcher? The closest comparison is the relationship between the placekicker and the holder in football. We need think back no further than 2003, when the Patriots were hesitant in releasing slumping punter Ken Walter because Adam Vinatieri was so comfortable with Walter as a holder. They finally cut Walter following the game of Nov. 30, only to bring him back after one game. But does a holder need special skills for special kickers? I'm sure Coach Bill would need a half-hour to explain it, one way or the other.
Knuckleballers aren't the only pitchers with personal catchers. Steve Carlton became wedded to Tim McCarver in Philadelphia. For years, Greg Maddux had to have Eddie Perez, not Javy Lopez, in Atlanta. And the Yankees paired up Randy Johnson with Flaherty last season when it became clear Randy was not comfortable with Jorge Posada. But none of these situations stack up to the dynamics of a knuckleball pitcher and his catcher.
This is the reason most managers are happy they don't have to deal with knuckleball pitchers in the first place.
''Two years ago," says Bowa, who has managed the Padres and Phillies, ''I asked someone when the Red Sox were in the playoffs if someone has ever won a World Series with a knuckleballer in the rotation. I mean, so many bad things can happen."
Joe Torre knows all about knuckleballs, having managed Phil Niekro for many years.
''Don't forget," says Torre, ''I also caught him for a long time, and that was when he was a reliever. I had to catch him in the eighth and ninth innings." Being the sanguine guy he is, Torre maintains he never got overly stressed watching Niekro work.
''I don't recall specific balls that got away leading to big runs, but I'm sure it happened. If one got by, it was because it was pretty much an uncatchable ball. You just have to learn to live with it."
But for every Joe Torre, there are about 10 Larry Bowas.
''I had one, Steve Sparks, and it was an issue," Bowa confides. ''I was always worried."
What Bowa did see Monday night is why there was such a fuss about Doug Mirabelli.
''He is special," Bowa says. ''You can see that. It has to improve Wakefield's confidence."
That's no doubt true, but Wake is going to need some time before he can stop feeling some culpability on the subject of Josh Bard.
''I always say it takes a special person to play here," says Wakefield, ''and he had the personality and character to do it."
But he's now 3,000 miles away, and the reason is that devilish pitch, the one capable of changing a life.
John Flaherty: How's that retirement coming along?
Bob Ryan is a Globe columnist. His e-mail address is email@example.com.