Red Sox closer Craig Kimbrel was tipping his pitches. Eric Gagne let Boston know.

Bob Nightengale | USA TODAY

BOSTON — He is the greatest closer in Los Angeles Dodgers’ history, revered in Los Angeles for his magnificence, and considered one of their all-time legends.

Now, Eric Gagne might be as welcome as an I-5 freeway pileup in Los Angeles if the Dodgers’ don’t win their first World Series championship since 1988.

Gagne, 42, became the most welcome snitch in Boston since Whitey Bulger, secretly informing his good friend, Red Sox manager Alex Cora, that his closer, Craig Kimbrel, was tipping his pitches.

Cora jumped on the information, passed it along to his pitching coach and video staff, and voila! his struggling closer is now fixed.

“We feel confident that he’s back," Cora said, “and that he’s going to dominate.”

Yep, just in time for the World Series when the Red Sox host the Dodgers in Game 1 beginning Tuesday night at Fenway Park.

Pardon the Dodgers for not getting nostalgic and enlisting Gagne to throw out a ceremonial first pitch when the series shifts to Dodger Stadium, wishing he simply would have kept his thoughts to himself.

“I’ve got a lot of friends around the league," Cora said, “the network is a big one. People are always paying attention. They always text or call and we run it through the coaching staff."

Cora didn’t want to publicly identify Gagne for fear of the backlash in Los Angeles, but when asked to identify the area code that originated the text message, the one that could be responsible for the Red Sox’s fourth World Series title in 15 years, he broke under the pressure.

“Montreal."

Ah, yes, the hometown of one Eric Serge Gagne, who was a teammate with Cora for seven seasons, six in Los Angeles, and one in Boston.

“Sometimes," Cora said, “you get so focused on mechanics that you forget about the simple stuff. He was tipping his pitches for two weeks."

And, sometimes, it pays to have great friends.

MORE WORLD SERIES:

Cora and the Red Sox staff knew something strange was going on during the postseason. Kimbrel was getting his saves, but getting clobbered at the same time. The Yankees and Astros were laying off his slider, and whacking his fastball all over the ballpark.

They just couldn’t figure out why.

It turned out, Gagne detected, that Kimbrel’s glove was pulled tighter to his beard when he threw his breaking ball than his fastball. He was also turning his head toward home plate and picking up the catcher’s target earlier on the fastball than the breaking ball.

“You could see the difference in the swings they were taking, that’s for sure," Red Sox starter Rick Porcello told USA TODAY Sports. “They weren’t swinging at everything, and taking good hacks. Once he found out he was tipping his pitches, all of a sudden the fastball was getting on them, and they were swinging and missing at the breaking ball."

Kimbrel is one of the greatest closers in the game, with the second-highest career save percentage in Major League Baseball history, (90.7%, 333 saves in 367 opportunities). He yielded the third-lowest opponent’s batting average (.146) and was fifth in strikeouts per nine innings (13.66).

Suddenly, the Yankees and Astros were treating him like a human piñata. He didn’t blow a save, but he gave up at least one run in each of his first four postseason appearances against the Yankees and Astros, yielding six hits, five earned runs and five walks in 5⅓ innings. He threw 41 breaking balls, and only nine times did anyone bother to swing. Just five missed.

“It happens," Porcello said. “You’re getting hit around, and you don’t even know why. It could be anything from you taking two deep breaths before a fastball, and one deep breath before a breaking ball.

“Tipping is one of those things that can be tough to figure out. When you’re in the heat of a moment, your body is doing certain things for a reason, and you don’t always feel it."

Cora and the Red Sox staff never saw it either. It took Gagne, sitting on his couch pulling for Cora, to discover the flaw. He sent a text message to Cora immediately after Game 4. Cora had Gagne and Kimbrel exchange text messages. Soon, Red Sox pitching coach Dana LeVangie and the video staff got involved.

They moved Kimbrel’s hands towards his belt to start his delivery, and just like that, the Astros had no idea what was coming.

“When he was warming up and he had his hands at the belt,” Cora said, “I looked at the [Houston] dugout and there was a lot of looking around. I was like, ‘yeah. All of a sudden they were taking fastballs right down the middle. They took some bad swings on sliders.

“We just played two of the most clever teams in the big leagues. He’s probably been doing it for a while. Too bad that it took us so long to figure it out."

Now, Kimbrel doesn’t have any fear about espionage, or worry that he became hittable overnight. He can relax now, letting his sheer talent take over in the World Series.

“I've been battling it for a while and couldn't find a good place to not hide it," Kimbrel said. “I was getting a little frustrated, mad at myself just because I couldn’t get out of some things.

“It just feels good to throw some pitches and have them not know what was coming."

Just in the nick of time.

“I’m sorry Boston that I gave quite a few of you heart attacks the last few days," Kimbrel said.

“But we’re all good now."

And for Eric Gagne, well, he’s never been more popular in Boston.