A year ago, Nationals General Manager Mike Rizzo was prepared to trade four young players to the Kansas City Royals for former Cy Young winner Zack Greinke, the deal falling apart only because Greinke, with a full no-trade clause, refused the Nationals’ nine-figure contract offer in exchange for accepting the trade.

But the Nationals’ thirst for a front-line starter to join Stephen Strasburg and Jordan Zimmermann atop their rotation never lessened, and on Thursday the team reportedly pulled off a blockbuster deal for Oakland Athletics lefty Gio Gonzalez in exchange for four of their best prospects. Keith Law of ESPN.com first reported details of the trade.

In exchange for Gonzalez, a 26-year-old who has won 15+ games and thrown 200+ innings in each of the past two seasons, the Nationals are giving up three pitching prospects – right-handers Brad Peacock and A.J. Cole, and lefty Tom Milone – plus catching prospect Derek Norris. Peacock, Cole and Norris ranked third, fourth and ninth, respectively, in Baseball America’s recent list of the Nationals’ top prospects. All were drafted in the fourth round or higher.

It was a lesser haul than the one the Nationals were willing to send to the Royals for a Greinke a year ago – that deal would have cost the Nationals at least one from a group that included Zimmermann, closer Drew Storen or second baseman Danny Espinosa, plus additional prospects.

But at the same time, Gonzalez is not without flaws. A power arm who ranked fourth in the American League in 2011 with 8.78 strikeouts per nine innings, he also led the league in walks, with 91, a year after finishing second with 90. It also appears that he benefited from pitching in Oakland’s cavernous Coliseum the past four seasons, recording a career ERA of 3.56 at home versus 4.32 on the road.

Still, the Nationals, whose offseason to this point had been marked by high-profile misses and low-profile hits, have suddenly taken a major step in their quest to contend for a playoff spot as soon as 2012. With Strasburg, Zimmermann and Gonzalez atop their rotation, the Nationals have three young, controllable power-arms (Gonzalez doesn’t become arbitration-eligible until 2013 and is under team control until 2015) that could form the nucleus of a formidable pitching staff for the next four-plus years.

“Whatever team is willing to . . . put me in their rotation,” Gonzalez said Wednesday in an appearance on MLB Network Radio, “I’d be more than happy to shine like a star there.”

The trade, which cost the Nationals dearly in prospects but relatively little in dollars, is certain to renew speculation that the Nationals will make a late run at free agent first baseman Prince Fielder – whose price tag could hit $25 million per year for seven or more years – in an all-out effort to contend with Philadelphia, Atlanta and Florida in the suddenly ultra-competitive NL East division.