Adrian Gonzalez, Josh Beckett, Carl Crawford and Nick Punto were sent westward for James Loney and four prospects. It was salary relief, rather than the package received in return, which made the Sox ship three of their most recognisable players.
Now, with the dust settling on the blockbuster deal, the attention will turn to the team the Sox are putting out on the field. Without three of their four highest-paid players, how good are the guys the Sox have left?
It's hard to suggest that Pedro Ciriaco, who was released by the Pittsburgh Pirates after playing just 31 games, can be one of the best players on the Red Sox.
However, there's no denying that he has been amazing; he now has more than a quarter of a season under his belt and has not slowed down. In his 41 games Ciriaco has hit at a .351 clip with 14 RBI and nine stolen bases in nine attempts. He also has seven three-hit games and is 11-for-14 in games broadcast nationally on Fox.
It's likely nothing more than an extended hot streak but Ciriaco has been one of the bright spots for the Red Sox in 2012.
Prospect Ryan Lavarnway might be lurking on the catching horizon but Jarrod Saltalamacchia has made the job his own this year.
Despite his poor .228 batting average and preponderance for striking out a lot (31.4 percent of the time), he has hit 21 home runs and might end up breaking Carlton Fisk's franchise record for home runs by a catcher.
Will Middlebrooks made national headlines almost as soon as he came up to the big leagues in May, as his strong start took the starting third baseman job from Kevin Youkilis.
After hitting .316 with six home runs and 21 RBI (all of which lead the team), the Sox's front office were loath to send him back to Triple-A Pawtucket, and so began a juggling act involving four players and three positions. Adrian Gonzalez was sent to the outfield for 18 games but the situation had become untenable and Youk was traded to the Chicago White Sox.
That left Middlebrooks as the present and future for Boston at the hot corner and that's perfectly fine. He was hit by an Esmil Rogers pitch in an August 10 game against the Cleveland Indians, and that might have ended his season.
Felix Doubront has had a bad few months. After an April and May which saw him pitch like the ace of the staff, Doubront has really struggled. A 5.18 ERA in June has been eclipsed by an 8.68 mark in August.
However, it could be down to fatigue. He has pitched 122.2 innings this year; before this season he had a total of 35.1 IP in his career. If the real Doubront is the one who started the year 6-2 with a 3.46 ERA, he could be a very good young member of this rotation.
Cody Ross has turned out to be an excellent signing for the Red Sox. Picked up in the offseason for relatively short money, Ross has solidified an outfield which was in turmoil for much of the year. He's hitting .271 with 19 home runs (third on team) and 62 RBI (first).
Just as 2010 was, 2012 has been a lost season for Jacoby Ellsbury. He's missed almost the entirety of both years with injuries which weren't due to fragility; Adrian Beltre ran into him two years ago and he stumbled into the second base bag earlier this season.
The season between those, though, was spectacular, and would have won him the MVP Award if it hadn't been for an otherworldy performance from Detroit's Justin Verlander.
This has been a bad year for Jon Lester (as it has been for most of his teammates). The man who has never lost more than nine games; never had a below-.500 win-loss record; and, has had an ERA below 3.50 for each of the last four years has been having a nightmare season.
Lester is 8-10 with a 4.98 ERA and 1.36 WHIP. In his 26 starts, he has only gone more than seven innings on three occasions, and has allowed four or more runs 13 times (including an 11-run disaster against the Toronto Blue Jays).
However, there's still a very good pitcher there. In his last three starts he's looked better, winning all three with a 2.25 ERA. There's been no word of an injury but something was wrong this year. If he can be the starter we knew from 2008 to 2011, he can be a great pitcher.
With the retirement of captain Jason Varitek, Dustin Pedroia was looked at as the heart of the team; as one of its leaders, alongside David Ortiz. The dysfunction that has engulfed the clubhouse this season might fly in the face of that but the 2008 AL MVP and 2007 Rookie of the Year is one of the faces of this Red Sox club.
The batting average has come down a little from his career numbers and his power has taken a big step back from the career-best 21 he hit last year, but he's still one of the game's best second basemen.
David Ortiz will be a free agent again at the end of the 2012 season. Re-signing him was already a priority before the Red Sox traded away their other big middle-of-the-order bat. Now bringing him back for 2013 (and probably 2014, since he'll want a multi-year deal and the Sox will be more desperate than they were last offseason) is a big priority.
He's been injured lately, and while he was 2-for-4 in his return from the DL Friday night, he looked hurt. Papi was clearly fine at the plate but he was limping around the bases and to and from the dugout. You might not see him for a while, perhaps not for the rest of the season, but he still needs to be back next year.
Ortiz has been Boston's best hitter. Despite missing more than a month, he still leads the team in home runs (23) and second in runs (66) and RBI (60). His .318 average is most for players with more than 150 PAs.
Clay Buchholz' numbers do not look good. They likely won't look good even when the season ends, but they're very misleading.
Coming off a back injury which ended his 2011 season before the All-Star game, Buchholz was rusty out of the gate. He gave up at least five earned runs in each of his first six starts, and did not have a start where he allowed fewer than two until his 12th appearance of the year.
His last start was a disaster, granted, but it ended a stretch of dominance which had totally turned his season around. In the six starts before that, he was 3-0 with a 1.53 ERA and 0.89 WHIP.
When the Red Sox were looking at blowing up their team, Buchholz' name was likely the only one on a piece of paper headed by the word 'untouchable'.