Few, if anyone, have better grasped baseball’s fundamental nature than Derek Jeter. A lack of emotion, the ability to shake off whatever occurred the prior day, serves you extremely well.

So perhaps Jeter, in this dark hour, still possesses the cold blood to appreciate this reality: Thursday’s setback was more devastating to him, personally, than it was to his team.

If you’re a Yankees fan, today you probably should worry more about your captain and less about your ball club.

“I’m happy with Nixy. I’m happy with Nuny,” general manager Brian Cashman said, referring to Jayson Nix and Eduardo Nunez. “But I would be happier with Derek.”

Cashman delivered the news, before the Yankees finished their series with Arizona at Yankee Stadium, that Jeter had suffered a “small crack” in the area of his left ankle that he fractured in last year’s American League Championship Series Game 1.

The reality is that, because of that injury, the Yankees never knew what to expect of Jeter in 2013. It would’ve been folly to pencil him in for another 216 hits he delivered in 2012, for anything approaching the 133 starts at shortstop and 25 at designated hitter that he made while turning 38.

We’re continuing to appreciate just how heavy a toll Jeter and the Yankees exacted by pushing him so hard last year, starting him in 66 of the final 67 games in their successful effort to hold off Baltimore and capture the AL East. We’re certain Jeter will express no regrets over those decisions and the consequences. Whether his determination to return by Opening Day actually caused this setback is an open question, one that will be asked of the captain next week when he addresses the media at Yankee Stadium.