It's not the biggest personnel mistake in Red Sox history -- an honor already reserved for owner Harry Frazee's decision to sell a plump pitcher-outfielder to the New York Yankees some 80 years ago -- but it's got a pretty good claim to second-place on that list.
When baseball people see Roger Clemens -- still going strong at 40, nearing career victory No. 300 -- they feel compelled to ask former Red Sox general manager Dan Duquette exactly the same question Jay Leno asked of Hugh Grant:
"What were you thinking?''
Fired 16 months ago, Duquette isn't talking. Duquette's now-famous explanation -- that Clemens was embarking on "the twilight of his career'' -- came to ultimately haunt Duquette and, just maybe, motivate the pitcher himself.
With the benefit of hindsight, Duquette's contention now seems absurd. Since leaving Boston, Clemens has gone on to win 107 games, three Cy Young Awards, two mythical pitching Triple Crowns and two world championships.
But in the context of the period, the argument was at least debatable. After all, in a stat line that some Clemens-bashers can recite faster than their own cell phone numbers, the once-and-future ace was a decidedly mediocre 40-39 in his final four seasons in a Red Sox uniform.
Moreover, Clemens was showing signs of wear and tear. He made two trips to the disabled list in those four seasons: once for a month in 1993 and another time, for better than two months in 1995. (To put that in perspective, his previous trip to the DL had come back in 1985 when he required shoulder surgery).
Privately, Duquette seethed that Clemens had been out of shape when the replacement spring gave way to an April settlement. Bothered by nagging hamstring and groin pulls, Clemens didn't pitch until the first week of June that year and the Sox rode Tim Wakefield's dancing knuckleball -- not Clemens' fastball -- to their first division title in five seasons.
That October, the Sox were summarily swept by the Cleveland Indians in the Division Series, with Clemens unable to double his meager postseason win total (he won exactly one game in four visits to the playoffs) as a member of the Sox.
Duquette took a look at Clemens' declining regular-season performance, some spotty conditioning in the strike year and a career-long inability to perform in the playoffs and decided the Sox could do better. A ludicrously lowball offer had the desired effect: it drove Clemens out of town.
But had Duquette looked closer -- or more objectively -- he would have found some explanations for Clemens' blue period with the Red Sox.
"I think Roger was in transition phase then,'' suggests a club source. "I didn't see the same velocity, to the extent that I remember, that I had seen from him in 1980s and early 1990s.''
Indeed, several former batterymates, including one-time Sox catcher John Marzano, say that Clemens began experimenting more and more with a split-finger fastball in the mid-90s.
"It took him a while to command that pitch,'' said Marzano, now a TV analyst in his native Philadelphia. "For a while, he was dominant he could beat you with two pitches -- his four-seam fastball and his slider. That's all he needed. But then his fastball started to be 92-93 (mph) instead of 98 and he had to make some adjustments.
Clemens had tried to introduce a forkball or split-finger fastball in the early 1990s, but then-manager Joe Morgan urged him to, as only Morgan could put it, "forget the forkaroni and go with Powder River (Morgan's delightfully antiquated term for the fastball).''
By 1993 and 1994, with Morgan gone and his velocity dipping, Clemens had no choice.
"At the beginning,'' recalls Marzano of the experimentation phase, "it would float up there. He didn't have that good late break to it and it looked like a straight fastball in the high 80s -- very hittable.''
Later, Marzano watched Clemens, a perfectionist, master the pitch that he would later label, in almost an homage to Morgan, "Mr. Splittee.''
"It got to the point where he could throw it in the low 90s -- with plenty action on it. My goodness. I guarantee he worked relentlessly to develop that pitch.''
Though Red Sox fans -- at times equal parts devout masochists and conspiracy theorists -- have convinced themselves that Clemens, buoyed by a long-term contract, mailed in his final four years.
Only when he was given a four-year, $31.5 million deal by the Toronto Blue Jays, they claim, did Clemens again dedicate himself to the cause.
"I suppose you could say that maybe there was a shred of complacency there (in the final few years in Boston),'' said the Sox official. "But I never saw his intensity reduce or his work ethic diminish.''
Marzano recounts long runs around the banks of Boston's Charles River as further support and adds there were many spring training runs which began as early as 6 a.m., punishing mini-marathons that few ever witnessed.
Poor support -- from his relievers and his hitters.
In 1994, when Clemens was just 9-7 despite a 2.85 ERA, the Sox managed just 15 runs in his seven defeats, scoring more than one run just once in those losses.
Despite failing to reach double figures in wins, Clemens had the lowest hit-per-inning ratio in the league and finished second in the AL in strikeouts and ERA.
In 1996, meanwhile, Clemens had seven leads blown by the bullpen. How different would Duquette's evaluation have been if Clemens had finished, say 16-11 instead of 10-13, especially when Clemens was 6-2 with a 2.08 ERA -- including another 20-strikeout, no-walk gem -- in his final 10 starts.
Hinting at the frustration he no doubt feels about his final four years in Boston and the rampant criticism he faced, Clemens has more than once said that had he had the incomparable Mariano Rivera -- or some other late-inning equivalent -- at his disposal, "I wouldn't be standing here, talking to you'' about approaching No. 300.
Translation: With someone other than Jeff Russell or Heathcliff Slocumb closing out games in his final Red Sox seasons, he would already have reached the magic number and begun enjoying his retirement.
Another popular New England parlor game involves debating whether Clemens would have been as successful had he never left Boston.
That's impossible to answer, but no less fun to ponder. And frankly, for a generation of jilted Red Sox fans, it's all they've got.
Sean McAdam of the Providence (R.I.) Journal covers baseball for ESPN.com.