BOSTON -- Dave Dombrowski’s story, the one he stuck to throughout the season, is that he never stopped believing in Rick Porcello as an elite top-of-the-rotation starter, maybe even one of the best in baseball.

Easy to say that now, right?

But long before Porcello went 22-4 with a 3.15 ERA for the Boston Red Sox and finished on top in the American League Cy Young Award voting that was revealed Wednesday night, he was a first-round draft pick of a Detroit Tigers team run by Dombrowski. It was Dombrowski who gave Porcello a $3.5 million signing bonus out of high school and brought him to the big leagues at age 20. And although Dombrowski traded Porcello after the 2014 season, that was mostly about money.

“At the time, we knew what it would take to sign him, and we weren’t in a position to be able to do that. That made the difference for us,” Dombrowski, who reunited with Porcello after taking over as the Red Sox president of baseball operations in August 2015, said late in the season. “However, we always liked him. When we drafted him, we thought he was going to be a No. 1 starter at the big league level.”

Yet Porcello was just another member of the band, never a front man, in a star-studded Detroit rotation that featured co-aces Justin Verlander and Max Scherzer. Porcello never seemed to get any better, either, his ERA plateauing from 2010-13 after a promising rookie year in 2009.

Porcello’s career ERA entering this season: 4.39.

If anyone truly believed in Porcello, 27, it was former Red Sox general manager Ben Cherington, who not only traded for him but also signed him to a four-year, $82.5 million extension before he threw a pitch for Boston. But if Dombrowski can honestly say he always thought Porcello had ace potential, maybe he can explain why anyone should believe the right-hander’s breakthrough 2016 season wasn’t merely an outlier in a career spent in the shadows of more accomplished pitchers.

“He’s really improved as an overall pitcher,” Dombrowski said. “Just the ability to change speeds, I mean, his changeup, his curveball, he cuts the ball. He’s really got a better pulse of changing the [hitter’s] eyesight on various pitches. You really see the growth. I think he’s taken another step further from what he was in Detroit.”

Indeed, Porcello evolved into an honest-to-goodness five-pitch pitcher this season. Whereas he previously relied on his curveball in some years and his cutter in others to offset his signature sinker and his four-seam fastball, he threw those secondary pitches and his changeup with almost equal frequency this year.

According to FanGraphs, Porcello went to his curveball 13.7 percent of the time compared to 12.4 percent with the cutter and 12.1 percent with the changeup. It marked only the second time in his career that his usage of all three pitches reached at least 12 percent, and he deployed them in a fashion that allowed him to exploit the vulnerabilities of individual hitters.

“Myself, [pitching coach] Carl [Willis], [bullpen coach] Dana LeVangie, we had conversations about attacking guys and kind of blending my mix of pitches in and attacking their weaknesses,” Porcello said. “That sounds like something you should always do, but when you have limited weapons to go into an at-bat with, there’s not a whole lot of different things you can do.”

Porcello also finally accepted who he is as a pitcher. Despite being the 14th-highest paid pitcher in baseball this year based on average annual value, he will never be a flame-throwing strikeout machine, a la classic aces Verlander and Scherzer. Instead, he’s a sinkerballer who induces enough grounders to kill a small ant farm.

And after desperately trying to be the former during a dreadful first season with the Red Sox in which he matched his career-worst 4.92 ERA, he realized there isn’t anything wrong with being an exceptional form of the latter.

“I’m not going to go out there and blow 98 [mph] by guys or have some nasty wipeout pitch, but I can go after a lineup with my repertoire,” Porcello said. “Hopefully I have a weapon for each hitter, and the things they don’t like to hit, I can go after them with. Getting back to understanding how I’m going to get guys out, how I’m going to set guys up, how I’m going to limit damage, once that clicked, I had something I could kind of grab onto and build off.”

There’s little denying that Porcello benefited from tremendous run support. The Red Sox were the majors’ highest-scoring team, and when Porcello pitched, they went crazy, averaging 6.83 runs per game. And Porcello got help from reliable defense, a necessity for a pitcher who doesn’t miss many bats. Opponents batted .269 on balls in play, down from .333 in 2015 and .308 throughout his career.

Those factors would seem to indicate Porcello might be due for some regression next season. But he also allowed three or fewer earned runs in 27 of his 33 starts and pitched into the seventh inning 23 times, remarkable consistency that proves good fortune was hardly the sole reason for Porcello’s success.

So maybe the season of Porcello’s life is repeatable. Maybe he can be the anchor of a rotation. Maybe Dombrowski was right all along.

“I mean, this guy won 14 games as a 20-year-old, so he’s always been a good pitcher,” Dombrowski said. “People don’t realize how many games he’s won at the big league level for his age. He’s got great makeup, great work ethic, very competitive. I think he’s settled in with his experience, realizing his own abilities. He’s become a much better overall pitcher.”

Perhaps even for years to come.