It was the end of an era in the Bronx on Friday, as a grateful and content Andy Pettitte officially announced today that he has walked off the mound for good.

With his wife at his side, the Yankees' lefthander announced his retirement from baseball in a news conference this morning at the stadium.

Pettitte spent 16 years in the big leagues, including 13 with the Yankees, winning five World Championships, three All-Star Game selections, and leaves as the winningest playoff pitcher in history.

"I believe I'm done. I wouldn't be doing this right now if I didn't believe I was done. I'm not going to play this season. I can tell you that 100 percent," said Pettitte. "You can never say never. But I don't think that I'll be pitching again. I'm looking forward to this next chapter in my life."

The 38-year-old pitcher said that while his body is ready to still play, his heart is "not where it needs to be." He said that he does not have the same fire to compete like he know he must.

"I can envision, I know exactly what it feels like to be here. And it didn't feel right for me anymore,” said Pettitte. “Didn't have the hunger, the drive."

Pettitte said he seriously started contemplating retirement when he reinjured his groin this season.

He said that the upcoming trial against former teammate Roger Clemens and his use of performance-enhancing drugs had to bearing on his decision.

"I would hope that anyone that has followed me through that whole situation would know that that has not had any effect, I mean zero, on my decision," he said. "I would never let that interfere with that decision, that life decision, through me and my family."

He also hinted at a possible future elsewhere within the organization, saying he feels he could do more for the team than just pitching every five days.

"I'm done with baseball. I'm not going to be pitching for the Yankees every five days anymore. But I don't like the word retired because I'm not done with work," Pettitte said.

He must now prepare for a life without pitching.

"Even if it's a little uncomfortable for me, you enjoy when the crowd's getting into it and the cheering and stuff like that,” he said. “I'm sure that'll be difficult to a certain extent, but it'll also be nice, because I don't feel I need that in my life."

However, he said right now he's looking forward to spending time with his family, coaching his son's baseball team, and watching his daughter play volleyball.

His departure makes him the first member of the “Core Four” to retire, leaving Derek Jeter, Mariano Rivera and Jorge Posada to carry on. The four won World Series titles in 1996, 1998, 1999, 2000 and 2009.

Pettitte said coming back to New York after a stint in Houston Astros and helping the Yankees win another championship was among his greatest accomplishments.

He went 11-3 last year, despite missing time due to injury.

Fans say his departure is a big blow to the team.

"It's one of the worst news to hear if you're a Yankee fan cause, come on, the man has been like one of our true aces for the last couple of years,” said one Bronx Bombers fans.

"That is very sad for us Yankee fans. It's a very sad day,” said another. “I think it's gonna be hard for them to make it to the playoffs without Andy."

Most fans told NY1 that they think Number 46 deserves to be in the Hall of Fame, despite admitting to the use of Human Growth Hormones.

Pettitte's decision leaves the Yankees with some holes to fill in their pitching rotation. C.C. Sabathia and Phil Hughes are the only guarantees with pitchers and catchers reporting to spring training in about two weeks.