It's official, Andy Pettitte, he of the 18 career playoff victories, will make the Game 2 start against the New Hampshire Fisher Cats Thursday night at Waterfront Park.

The left-hander was originally scheduled to pitch in tomorrow’s Game 1, but was moved up a night to keep him on normal rest.

He’ll throw four innings or 65 pitches, according to Yankees manager Joe Girardi. The last hurdle for Pettitte to clear was an early bullpen session yesterday morning, which he passed with flying colors. He threw 20 pitches and reported no pain.

For Thunder fans, seeing Pettitte on the hill will be the thrill of a lifetime. For the players, however, it could mean the difference between a series win or an early exit.

Pettitte will likely oppose right-hander Zach Stewart, one of New Hampshire’s two aces who have befuddled the Thunder offense all season long.

Although he’s only come away with one win, Stewart has worked to a 3.29 ERA against Trenton in five games, and has held the team to just one longball, which came off the bat of the since-promoted Brandon Laird.

Adam Warren, the tentatively scheduled starter for Thursday night, will more than likely be pushed to Friday’s Game 3, which will be played at New Hampshire’s Merchantsauto.com Stadium.

Pettitte’s appearance marks the third player to rehab with the Thunder during the playoffs. Former Yankees outfielder Hideki Matsui showed up in 2006, and reliever Tom Gordon did the same in 1999.

The Thunder lost both of those sets.

Neither of those players, however, had a postseason resume of anything close to Pettitte’s caliber.

In his career, the “Core Four” member has dominated in the playoffs. He’s gone 18-9 overall, including clinching victories in the ALDS, the ALCS and the World Series last season.

As for the opposition, it doesn’t sound as if the Fisher Cats are exactly shaking in their boots about stepping into the box against him.

“He’s a Hall of Famer in my book. If we get to face him in the playoffs, it would be fun,” All-Star center fielder Darin Mastroianni told the Manchester Union-Leader, “but we’re going to play to win. He’s not going to be the deciding factor.”