The Pirates' highest previous grade in those annual rankings was No. 8, approaching the 2013 season.
Coming in the wake of a 94-win season, is this a perfect storm for franchise renaissance?
"It is a nice honor, nice recognition from one of the more respected periodicals," Pittsburgh GM Neal Huntington said. "Otherwise, it's not something we pay a lot of attention to."
Baseball America accorded this No. 1 ranking a year ago to the Cardinals, who went on to edge the Pirates for the National League Central title with significant contributions from several prospects highlighted in that report. They included first baseman Matt Adams and right-handers Carlos Martinez, Shelby Miller, Trevor Rosenthal and Michael Wacha.
Best-of honors shifted to the Pirates, according to the publication, "for their combination of potential impact talent, depth and big league-ready prospects, plus a strong 2013 Draft class."
Right-hander Jameson Taillon and outfielder Gregory Polanco top the "big league ready" class, and 2013 first-round picks outfielder Austin Meadows and catcher Reese McGuire highlight the future depth another focus site, MLB Draft Insider, called "an absolutely absurd amount of quality and quantity in the outfield and ... right-handed pitching."
"We have said all along that maintaining success is harder than achieving it, and sustainability is what we strive for," Huntington said. "Such recognition for having a lot of talent in the system testifies to the success of that approach."
Tom Singer is a reporter for MLB.com and writes an MLBlog Change for a Nickel. He can also be found on Twitter @Tom_Singer. This story was not subject to the approval of Major League Baseball or its clubs.