It’s been a rough season for David Ortiz and the Red Sox, currently in the AL East cellar. (Darren McCollester/Getty Images)

On Wednesday afternoon, the Boston Red Sox cut veteran catcher A.J. Pierzynski, called up Christian Vazquez from Class AAA Pawtucket and stuck him behind the plate that night, his big-league debut. There is no more symbolic move for a major league team in July. This season’s over. The future’s bright. Bring up the kids.

The lineup on Wednesday night against the Chicago White Sox not only featured Vazquez, but four other rookies – Brock Holt leading off and playing shortstop, Xander Bogaerts at third, Jackie Bradley Jr. in center and Mookie Betts in right. This kind of thing happens every summer somewhere, bringing a wide range of hopes, some realistic, some not.

What doesn’t happen every summer: The kind of flip-flop the Red Sox are experiencing. In a 10-season stretch from 2002-11, Boston averaged more than 93 wins, second only to the Yankees in that period, and made the postseason six times, winning two World Series – a consistent, wealthy juggernaut.

The past three seasons: a 69-win disaster under miscast Bobby Valentine in 2012, a remarkable run to a World Series title last year, and now this – a full reset, teetering on the brink of last place, on pace to lose 90 games.

First, let’s acknowledge how unusual this is. Sure, teams have won the World Series and then plummeted, but that normally involves something of a salary purge (see Florida Marlins, 1998). Given baseball’s robust financial health, salary purges don’t really happen anymore. And sure, teams have gone from worst to first. The 1991 Atlanta Braves and Minnesota Twins both did, meeting in the World Series, and eight teams have done it since.

But no franchise in baseball history has ever gone from last to winning a World Series to last again in a three-year span. So the Red Sox find themselves in this odd spot, with glory in their immediate past, unexpected misery in their present – and hope running out there onto the Fenway Park diamond for the rest of the summer in the form of players in their early 20s.

“Young players we believe in need to be given an opportunity,” General Manager Ben Cherington told reporters Wednesday. “But we can always learn how to do that from our experience. And ultimately, based on the team’s record, I didn’t do a good enough job finding – to this point, anyway – the right mix. That’s not particular to any one player or any one position. It hasn’t worked in the aggregate, so we have to learn from it and get better.”

What’s most instructive in figuring out how the Red Sox got here isn’t so much what went wrong this year (and there’s plenty), but how much went right in 2013. It started in the summer of 2012 with the blockbuster trade that sent right-hander Josh Beckett and first baseman Adrian Gonzalez to the Dodgers, cleansing the Red Sox of their collapse at the end of the 2011 season and sending the first signal that things would be different. Cherington then replaced Valentine, who won 69 games in a one-year black mark on the franchise’s history, with John Farrell, Boston’s former pitching coach who was then the Toronto manager.

Those are tone-setters. But think about the Red Sox’ good fortune during 2013. They signed veteran outfielder Shane Victorino for three years and $39 million, and he hit for the highest average (.292) and second-highest slugging percentage (.451) of his career. They lost their first two choices at closer – Joel Hanrahan and Andrew Bailey – to season-ending injuries, and watched Koji Uehara became the most reliable in the game, with a 1.09 ERA and 101 strikeouts in 74-1/3 innings.

They signed former catcher Mike Napoli to a one-year, $13 million deal, stuck him at first base, and enjoyed what amounted to a seamless transition defensively to go along with a career-high 92 RBI and an .842 OPS. They got a two-year, $10-million bargain in veteran Jonny Gomes, and watched as Daniel Nava, essentially an extra outfielder, posted an .831 OPS in 134 games.

Xander Bogaerts has a promising future, but has struggled in 2014. (Jared Wickerham/Getty Images)

Throw in the usual contributions from the remaining members of the 2007 World Series champs – 103 RBI from David Ortiz, a .301 average from Dustin Pedroia, a league-leading 52 stolen bases from Jacoby Ellsbury – and it was impossible to look around the Boston clubhouse and say, “He’s not doing his job.” The Red Sox led the majors in on-base percentage (.349), slugging percentage (.446), OPS (.795) and scored 57 more runs than any other team in baseball – more than a third of a run per game better than the second-most productive team.

Baseball, of course, is all about regression to the mean, so the Red Sox couldn’t possibly be expected to duplicate that success, individually or collectively. Ellsbury departed to the Yankees as a free agent, but basically everyone else returned. The results: last in the AL in runs scored (and a full run-and-a-half per game less than a year ago); last in slugging percentage (.365); next-to-last in homers and OPS.

The individual culprits: Nava’s OPS is down more than 200 points to .622, and he has eight extra-base hits in 181 plate appearances. Bogaerts, who appeared to be a star on the rise in wresting the third base job from Will Middlebrooks last postseason, is hitting .237 – including .109 since June 4 while slugging .145. Bradley, Ellsbury’s replacement, is hitting .218, Gomes just .239, and Victorino has played in just 21 games because of injuries. Middlebrooks has been hurt and in the minors. Pedroia’s average (.279), OBP (.346), slugging percentage (.380) and OPS (.726) are the lowest of his career.

Yet here’s what’s even stranger: That lineup Boston ran out there Wednesday night, the one with all those rookies, is the reason to believe this flip-flop could continue back the other direction. Boston’s minor-league system was ranked the best in the game at the end of 2013 by the trade publication Baseball America. Blake Swihart might be the best catching prospect in baseball, and lefty Henry Owens has dominated for two straight seasons. Both are still at Class AA.

Players like that are the reason, even in this situation, the Red Sox are still pursuing a contract extension with ace lefty Jon Lester, a 30-year-old three-time all-star who has the lowest ERA of his career.

“We have guys who are free agents in the offseason that we’d still like them to be here past this season,” Cherington said. “Everyone knows that. We’ll just see what happens.”

What will happen, over the rest of the summer, is the kids will play. They may end up in last, and put these Red Sox in an unprecedented worst-to-first-to-worst position. But more kids are on the way. And a summer of misery may become a summer of discovery at the Fens.