MLB

Yankees’ world blitzed when Curtis is plunked

TAMPA — It starts with a thud sometimes.

A “thwack.”

A baseball gets away from a left-handed pitcher and it runs in on the hands of a left-handed hitter, and maybe on Feb. 24 the reflexes aren’t as sharp as they’ll be on July 24, or even March 24, and so instead of glancing off the meaty part of the forearm, ball hits bone.

Ball breaks bone.

“Sometimes you look at a guy get hit and you immediately think to yourself, ‘Well that’s broken,’ and it winds up to be nothing,” Yankees general manager Brian Cashman said late yesterday afternoon. “And sometimes you think, ‘That’s no big deal,’ and …”

He smiled a forced, painful smile.

“That,” he said, “is baseball.”

And so Curtis Granderson goes away for 10 weeks, his right forearm fractured by a J.A. Happ fastball, and the Yankees’ spring gets even more interesting by suppertime than it was at breakfast.

Already Derek Jeter had taken some swings in the batting cage and some ground balls at shortstop and declared he’d be ready to play in a real game by March 10. Already Phil Hughes had left the premises to go soak in a pool trying to soothe his balky back. Already Cashman had fielded his daily quota of Alex Rodriguez questions, reaffirming that he expects A-Rod back by the All-Star break.

“His rehab is going well,” Cashman said, and he was in a playful mood when he said it, around 11 in the morning, chiding a small corps of reporters for trying to continually make the A-Rod story bigger than it is, as if that’s even physically possible.

By 4 in the afternoon, the playfulness was gone, he was serious as a tax audit, and looked like a man yearning to answer questions about the media making the A-Rod story bigger than it is, or about his third baseman’s heart belonging to Boston, or about the looming experiment playing Granderson in left and Brett Gardner in center that was sure to fill a few notebooks in the coming weeks.

“There is no left-field/center-field plan any more,” he said.

PHOTOS: YANKEES SPRING TRAINING

Spring had sprung a leak.

“Five pitches in, we got a little setback,” said Granderson, who was awfully at peace with the bad news given that shaving at least a month off his season affects his future every bit as much as it does the Yankees’ present. “Now we rest, recover, get it back, and get ready to play whenever that day comes.”

That day will be around the first week of May, assuming there are no setbacks, and the Yankees happened to pick this April to be packed with games, only two scheduled off days, in a season when they were already staring at a roster that is a little banged up and a little long and a little lacking in the “big, hairy monsters” that Cashman likes to call his sluggers — all before deleting Granderson and the 84 homers he’s hit the last two years from the batting order.

The beauty of spring is always the fact that there’s an endless supply of kids willing to crash through walls and stomp on nails if it means the manager will take an extra look at the 78 or 85 or 97 on their backs; but that becomes the burden of spring when you’re no longer looking at those youngsters as futures stocks and are instead trying to speed up the projection tables a bit.

A trade? Vernon Wells is a guy who makes sense, and the Angels will likely absorb most of the cost, but this isn’t a season-ending injury, just a spring-ender. Eduardo Nunez? It seems this is as good a time as any to let him sink or swim as an outfielder to get his energy and his bat in the lineup more often, but neither Cashman nor Joe Girardi seem inclined to change their mind on that.

“You never know how deep you are until you test it,” Girardi said. “We’re going to test it right now.”

Five pitches into a new season the whole picture can be toppled upside down, a thud and a thwack thwarting the best-laid of all pans. Spring training can feel like an endless slog sometimes; yesterday, it suddenly turned a whole lot shorter for the Yankees.

michael.vaccaro@nypost.com