TORONTO – Alex Anthopoulos is leaving the Toronto Blue Jays less than a week after the American League East champions were eliminated from the post-season, rejecting an extension to remain as general manager, according to multiple sources.

The stunning and franchise-altering departure comes with the looming arrival of Mark Shapiro, who was hired Aug. 31 and is scheduled to take the reins as president and CEO from Paul Beeston on Monday. While details are unclear at the moment, the issues leading to the split aren’t thought to be financial.

The two sides had plenty of time to work out an extension and what should have been straightforward became complicated. During his season-wrap news conference Monday, Anthopoulos said it was his decision not to negotiate during the playoffs, and added, “All I can say is I love being here, I love Toronto, I’ve always maintained that, and that’s probably as far as I’d go with that.”

Whatever the circumstances, the parting comes just as the franchise appeared set to turn the corner after ending a post-season drought dating back to 1993, and with the business of the off-season set to kick off once the World Series ends.

What comes next for the Blue Jays, who lost the AL Championship Series in six games to the Kansas City Royals, is a big question.

Shapiro is an accomplished executive who served as GM of the Cleveland Indians from 2002-10, winning the AL Central in 2007, before taking over as the team president. One possibility is that he takes over control of baseball operations with the Blue Jays, or perhaps hire a GM to execute his vision.

The departure of Anthopoulos also raises questions about the fate of his top front office lieutenants, including longtime assistant GM Tony LaCava, as well as manager John Gibbons, who is under contract through 2016 and will have 2017 guaranteed and a club option for 2018 added if he makes it to Jan. 1.

The Blue Jays were 489-483 under Anthopoulos, who replaced J.P. Ricciardi on the penultimate day of the 2009 season, posting three fourth-place finishes in the AL East, a fifth-place finish and a third-place finish before winning the division at 93-69 this year.

His signature move is likely to be the acquisition of Josh Donaldson last off-season from the Oakland Athletics for Brett Lawrie, Kendall Graveman, Sean Nolin and prospect Franklin Barreto, but he also pulled off perhaps the greatest trade deadline ever when he acquired Troy Tulowitzki, David Price, Ben Revere, Mark Lowe and LaTroy Hawkins in the span of four days while staying within his allotted payroll.

Prior to the 2011 season, Anthopoulos managed to dump roughly $81 of the $86 million owed Vernon Wells on the Los Angeles Angels, a move that set the stage for the competitive window he later established.

There were also trades with mixed results, such as the acquisitions of Lawrie, Brandon Morrow, Yunel Escobar and Colby Rasmus, not to mention sending Roy Halladay to the Phillies for Kyle Drabek, Travis d’Arnaud and Michael Taylor, who begat Brett Wallace, who begat Anthony Gose, who begat Devon Travis.

Anthopoulos also had some major swings and misses, most notably the blockbuster with the Marlins that landed Jose Reyes, Mark Buehrle and Josh Johnson, and the trade for R.A. Dickey with the New York Mets that followed as a result.

The Marlins deal, the one real outlier in his track record, may have been forced upon him, as it followed a messy 2012 that included three-fifths of the rotation suffering significant injuries in the span of a week, incessant rumours linking then manager John Farrell to the Boston Red Sox, Escobar taking the field with a homophobic slur across his eye black patches in Spanish, and Omar Vizquel publicly questioning the coaching staff in the final days of the season.

Players either drafted or signed as international free agents under his watch on the current roster include Marcus Stroman, Aaron Sanchez, Roberto Osuna, Kevin Pillar and Dalton Pompey, while Noah Syndergaard, Justin Nicolino, Adeiny Hechavarria, Anthony DeSclafani, Daniel Norris, Jeff Hoffman, Matt Boyd, Graveman and Nolin were among the prospects used in trades.