Burnett's career season with the Toronto Blue Jays in 2008 - he won 18 games and led the American League with 231 strikeouts - had persuaded the Yankees to sign him to a five-year, $82.5 million contract. The next three seasons persuaded them to trade him to the Pirates.
In pinstripes, he went 34-35 with a 4.79 earned-run average, leading the AL in walks once, batters hit by pitch once, and wild pitches twice. Even his crucial Game 2 victory against the Phillies in the 2009 World Series couldn't stop him from becoming a deserving punching bag in the country's largest and most demanding sports-media market.
"Those fans were great, and they were on me because I gave them a reason to," Burnett said Wednesday after allowing three runs over four-plus innings in the Phillies' 6-5 victory over the Orioles. "If I go out there and do what A.J.'s capable of doing, we don't even have this question."
So why didn't he? Burnett's time in New York provides convenient cause to doubt that he'll thrive in Philadelphia, in another Northeastern city where the pressure to perform will be higher than it was in Toronto or Pittsburgh.
Couldn't Burnett handle pitching for the Yankees? Did he regress without the presence and influence of Roy Halladay, his teammate for three years with the Blue Jays? Did the expectations that his contract created become a burden too great to bear?
"I tried to do more than I was capable of doing, to prove to myself and the world that I was worth it," he said. "After playing with Doc, I got away from the one-pitch-at-a-time theory in New York. It didn't matter if I didn't hit on a pitch or if my mechanics were off - I've got to make another pitch. That wasn't on my mind. It was, 'What's happening? I've got to fix this.' "
Burnett has long had a stubborn streak on the mound, and only later in his career, he said, has he been more willing to temper that stubbornness.
In 2005 with the Florida Marlins, for instance, when he was 28 and his repertoire consisted primarily of a mid-90s fastball and a sharp curveball, Burnett threw 44 change-ups in a complete-game shutout of the Tampa Bay Rays "just to shut people up." He threw four change-ups in his next start.
He remained just as inflexible with the Yankees, believing he threw hard enough to get away with pouring in four-seam fastballs to hitters, even though Yankee Stadium's inviting right-field wall is a mere 314 feet from home plate. It wasn't until he joined the Pirates and met his new catcher, former Phillie Rod Barajas, that Burnett realized he had to change his approach.
Because Burnett's fastball velocity had slowed as he'd aged, Barajas insisted that he use his sinker more frequently. The improvement was dramatic. Burnett's ratio of hits and walks to innings pitched dropped. The percentage of ground balls he surrendered increased. He emerged as the No. 1 starter on a Pirates team that last year reached the playoffs - hell, that had a winning season - for the first time since 1992.
"I'm not going to overdo anything here," he said. "I learned a lot in New York. I take it all as a positive. My three years there were not good at all, but believe me, it had nothing to do with the market. I'm older. I get it now."
So he could talk in depth Wednesday about the adjustments he needs to make before his next spring-training start, including picking up the catcher's glove sooner before releasing each pitch.
And he could saunter up to Ken Giles - the hardest-throwing prospect in the Phillies organization, with a fastball that has topped 100 m.p.h - and sound like a sage: "Enjoy it while you've got it, man."
A.J. Burnett is 37, and he still has the tattoos, still looks like the guy whose career was bound to come crashing around him in New York, but the Phillies are counting on him to be the different, better pitcher he was in Pittsburgh, and Burnett himself is, too.
Think about it. If a man spends 15 years in a profession and never has to learn or grow or overcome any obstacles, he pretty much wasted all those years, didn't he?