For the past several weeks, Derek Jeter has been doing what he has long done as the Yankees’ redoubtable shortstop for two decades: getting a head start on spring training by working out almost daily at the team’s complex in Tampa, Fla.

But Wednesday was different. Before he began his usual morning routine — fielding grounders, taking batting practice and waiting for more of his teammates to join him on the field in the coming days — Jeter called the Yankees’ majority owner, Hal Steinbrenner, to say he had come to a fateful decision: The 2014 season would be his last in the major leagues.

Steinbrenner, still in New York, having attended the inaugural news conference for pitcher Masahiro Tanaka on Tuesday, was about to board a plane to return to Tampa. But before he could, Jeter, 39, gave him the news that neither Steinbrenner nor any other member of the club’s front office had seen coming.

Hours later, Jeter made his decision public by posting a 14-paragraph statement on his official Facebook page that began with a simple thank you.