The natural rhythms of the baseball season remind us that summer never lasts. In places like New York, the postseason arrives with the cold snap of autumn, the first sign that winter is coming. This is when the Yankees make their mark.

They still have a chance for a glorious final image from this season. But unless they win eight more games, the Yankees of 2012 will be defined by two portraits of pain, flashing neon reminders of the subtler message the game tells its fans every year. We are all getting older, even the players who seem eternally young. And the end often comes without warning.

Derek Jeter, the Yankees’ captain and shortstop, dove to his left for a ground ball in the 12th inning of the first game of the American League Championship Series early Sunday morning against the Detroit Tigers. He has made this play countless times across 18 major league seasons and 33 postseason series.

But this time, Jeter did not get up. He gathered the ball but flipped it awkwardly as his body crumpled to the ground, his face contorted in pain. Jeter broke his left ankle on the play and is finished until spring training.