AP Baseball Writer
NEW YORK (AP) -- To Derek Jeter, it was just another day to get ready for spring training.
On a minor league field at the New York Yankees' complex in Florida, he took batting practice, fielded grounders and chatted with teammates. And then he drove away in his Mercedes, offering no hint that the countdown to his retirement had already begun.
Hours later, Jeter alerted the sports world: This will be his final season.
"I know it in my heart. The 2014 season will be my last year playing professional baseball," Jeter posted Wednesday in a long letter on his Facebook page.
"I have gotten the very most out of my life playing baseball, and I have absolutely no regrets," the shortstop wrote.
While it was no secret the team captain was getting close to the end of his brilliant career as he neared 40 -- especially after injuries wrecked him last season -- Jeter's announcement caught many by surprise.
In fact, some people wondered whether his account had been hacked. But it was quickly confirmed that one of the greatest players in the history of baseball's most storied franchise was serious.
A 13-time All-Star shortstop who led the Yankees to five World Series championships, Jeter was the last link to the powerful Yankees teams that won three straight crowns from 1998-2000. Longtime teammates Mariano Rivera and Andy Pettitte retired after last year.
"Derek Jeter is Mr. Yankee of his era," Yankees co-chairman Hank Steinbrenner told The Associated Press. "He was the face of one of the greatest teams ever."
Jeter was limited to 17 games last season while trying to recover from a broken left ankle sustained during the 2012 playoffs. He hit only .190 with one homer and seven RBIs.
"Last year was a tough one for me. As I suffered through a bunch of injuries, I realized that some of the things that always came easily to me and were always fun had started to become a struggle," Jeter wrote. "The one thing I always said to myself was that when baseball started to feel more like a job, it would be time to move forward."
"So really it was months ago when I realized that this season would likely be my last. As I came to this conclusion and shared it with my friends and family, they all told me to hold off saying anything until I was absolutely 100 percent sure," he wrote.
"And the thing is, I could not be more sure," he wrote.
His agent, Casey Close, said Jeter wanted to declare his intentions before the Yankees start spring training later this week so that his future status wouldn't be a distraction.
The Yankees open camp for pitchers and catchers on Friday. Jeter has said he's healthy and ready to go -- at 39, his next birthday is in June.
"Derek called me this morning to tell me that he planned to retire following the season," Yankees Managing General Partner Hal Steinbrenner said.
Said Los Angeles Dodgers manager Don Mattingly, a former Jeter teammate: "I'm excited for him. It's kind of nice to see him go out on his own terms."
Jeter is the Yankees' career hits leader with 3,316. He's ninth on the all-time list; a 200-hit season would put him in fifth place.
Jeter is a lifetime .312 hitter in 19 seasons, with 256 home runs and 1,261 RBIs. He has scored 1,876 runs, stolen 348 bases and is a five-time Gold Glove winner.
Added up, his numbers put him among the greats in Yankees history, with fans often invoking the names of Babe Ruth, Lou Gehrig, Joe DiMaggio, Mickey Mantle when mentioning Jeter's legacy.
But No. 2 is defined by so much more than his numbers. His backhanded flip in the playoffs, his diving catch into the stands, his speech to close old Yankee Stadium and his home run for career hit No. 3,000.
An October presence for so many years -- Jeter is a career .321 hitter in seven World Series -- he also became Mr. November in 2001. His winning, 10th-inning homer came shortly after midnight in a Game 4 that began on Halloween.
Jeter was the AL Rookie of the Year in 1996, the season the Yankees won their first World Series since 1978 and re-established themselves as a major force. He was the MVP of the 2000 World Series.
"He made me a better player and a better person," longtime teammate Jorge Posada said. "I'm so proud of our friendship and I love him like a brother. Derek was a true champion."