MLB

Yankees’ Jeter reaches 38th birthday in midst of slump

Derek Jeter goes into his birthday feeling fine at the plate. He does not go into his birthday performing well there.

The Yankee captain turns 38 today, but Jeter’s struggles have reached some alarming proportions. He began the season brilliantly, batting .397 with five homers, 15 RBIs and a 1.034 OPS in his first 28 games. After going 1-for-4 in last night’s 7-1 romp over the Indians, though, Jeter is hitting a meager .243 with two homers, 10 RBIs and a .594 OPS in his last 43 games.

“I feel all right [at the plate],” Jeter said yesterday, before saying Sunday was the exception since it featured Mets knuckleballer R.A. Dickey on the hill. “Other than that, I feel all right.”

Forty-three games is not a small sample — it is more than a quarter of a a season. Perhaps tellingly, Jeter had always torched the Mets — his lifetime average against them prior to this season was .381, which doesn’t include his 2000 World Series MVP performance. But Jeter went just 5-for-25 against the Mets, including 2-for-14 at Citi Field.

Jeter’s season average is now at .304, the lowest it’s been since the third game of the year. If he goes 0-for-5 or worse tonight, Jeter will have the unfortunate coincidence of dropping under .300 on his birthday. There are probably better presents than that.

On the other hand, if Jeter gets three hits today, he’ll tie Cal Ripken Jr. with 3,184 all-time hits, good for 13th best all-time.

Jeter is hitting .318 in 11 games on June 26. When asked yesterday if he wanted to know his birthday numbers, Jeter — not surprisingly — said no.

“To think that he’s still doing it at that age is really truly amazing,” Joe Girardi said. “I told him, ‘At our age, Derek, we don’t have to have birthdays anymore.’ ”

Jeter also went through a prolonged slump last season. But when he came off the DL on July 4, he hit .331 with 41 RBIs over the final 69 games of the season.

mark.hale@nypost.com