TRENTON — On sheer looks alone, new Thunder third baseman bears a frighteningly striking resemblance to Kevin Mahoney, the infielder who spent a few weeks with Trenton this summer.

And just like Mahoney, Rob Segedin made it to Double-A well before he had any business being there.

The Yankees’ third-round pick from this season was promoted Tuesday when second baseman Corban Joseph was placed on the disabled list for a problem in his right wrist. He’s not likely to see much — if any — time in the playoffs, but he was all smiles anyway.

“I got the call and I was really excited to come down here and help the Trenton Thunder in the playoffs,” Segedin said.

Obviously, a promotion to Double-A — for the playoffs, to boot — after spending just 24 professional games combined between Rookie and Short Season ball, comes with a massive helping of shock. Segedin’s case was no exception.

“My coach, Josh Paul, called me and said I was going to Double-A, and I literally had to ask him five times, I thought he was joking around,” Segedin explained. “He said, ‘No, seriously. You’re going to Connecticut tonight, pack your stuff.’”

With the Gulf Coast League Yankees and Staten Island this season, Segedin, a native of Teaneck, hit .244 with two home runs and 10 RBIs.

Although it’s not often that a club fails to sign its third-round selection (only the Mariners failed to do so this year), knowing that the Yankees — his boyhood team — who chose him made the decision to leave Tulane that much easier.

“To go with an organization that’s so dedicated to winning, and hopefully going through the organization, playing for an organization like that, that’s something I really wanted,” he said.

For a boy like Segedin, who grew up watching the Yankees and the Core Four dominate the late 90s and early 2000s, the opportunity to watch Andy Pettitte make a rehab start is going to be a career highlight for years to come.

“He’s on my team, at least for one day,” Segedin said, wearing a huge grin. “I’ve watched him, literally, since I started watching baseball. 1995 was when I started seriously watching baseball, seeing Jeter and all those guys. … Now that I’m on the same team as (Pettitte), it’s kind of cool.”