With a chance to slap the New York Yankees with a loss and hurt their playoff dreams, Uehara allowed a ninth-inning home run to Mark Teixeira to tie the game at Yankee Stadium.

Then, Chase Headley homered for a 5-4 victory.

The Yankees had one hit since the third before Teixeira drove a hanging splitter into the second deck in right field for his 21st home run this season, his first since Aug. 17.

“I’ve been pretty bad the last few weeks,” said Teixeira, who started the game in a 6-for-44 slide.

Uehara got Brian McCann to fly out. Headley worked the count to 3-2 and sent another splitter from Uehara deep into the right-field bleachers.

Yankees celebrations are never a good thing to the Red Sox.

UPDATE: Red Sox take Uehara out of closer role

Friday, The Boston Globe asked the question on every Sox fans’ mind: What is wrong with Koji Uehara?

A closer whose splitter made him a star now sees it flying out of ballparks. Were this an isolated incident, Sox officials could shake it off. But Uehara is in an extended slump, The Globe notes.

It’s not. In fact, manager John Farrell and staff are weighing whether to shut down Uehara for the season.

Probably a good idea. The Sox are going through a first-to-worst season, and whatever his problem Uehara now has it in his mind as well. He told reporters via a translator the loss was his fault, and he appeared to be taking this one hard.

It was his third loss in five appearances. In comments to Japanese media members, Uehara said his mechanics are flawed.

Farrell had this to say about Uehara’s pitching.

“The lack of finish to his split is what allowed a couple of pitches to stay in the zone late and led to a couple of home runs.

“From viewing and talking to Koji, it’s the finish. Whether it’s the intensity behind the delivery of the pitch on occasion, the first one to Teixeira had good depth to it for the swing and the miss. [When it’s not finished off] it stays in the middle of the plate and down, a natural stroke for lefthanded power hitters.”

Given his pending free-agent status, one wonders whether Uehara, closer for the 2013 World Series champions, might have thrown his last pitch for the Red Sox.

GM Ben Cherington is on record as wanting to re-sign Uehara, sees his August struggles as an aberration. But Uehara will be 40 before next season, and he will need a $15 million qualifying offer.

MassLive.com offered this perspective: Little was expected of Uehara when he came to the Red Sox as a late bloomer. He was just a piece to the puzzle. He exceeded expectations. Now, he’s come back to earth.

Koji Mania is over.

Farrell has closer options, including Edward Mujica and Junichi Tazawa.

Contributing: Associated Press