Today, they’re the New York Mets aces who rule the mound at Citi Field.

But just a few years ago, Noah Syndergaard, Jacob deGrom, Matt Harvey and Steven Matz were pipsqueak kids, unrecognizable as the major-league studs now racing toward the World Series.

The most startling transformation is that of Syndergaard, who was an awkward, doughy kid in a middle-school photo taken around 2005.

“Back in eighth grade, I was a chunkster,” Syndergaard recalled in a 2012 interview. “Kids would tease me for being overweight.”

One day, he told his father he wanted to join the YMCA and eat healthy — beginning his amazing transformation into a 6-foot-6 star athlete who graduated in 2010 from Mansfield Legacy HS in Mansfield, Texas.

DeGrom, too, is hardly recognizable in a 2007 high-school yearbook picture from Calvary Christian Academy in Ormond Beach, Fla.

Matz, an alum of Ward Melville HS in East Setauket, LI, bears the closest resemblance to his early self.

Meanwhile, Harvey, nicknamed the Dark Knight, tried to pull off a smoldering tough-guy look in his 10th-grade yearbook photo from Fitch Senior HS in Groton, Conn.