Major League Baseball is looking into the Joe Kelly incident in Houston on Tuesday night, a source told ESPN's Buster Olney.

The Los Angeles Dodgers' flame-throwing reliever sent a 96 mph fastball whizzing behind the head of Houston's Alex Bregman in the sixth inning on Tuesday night in more fallout from Houston's 2017 sign-stealing scandal.

Moments later, after a few more brushback pitches, Kelly mocked Carlos Correa with a pouty face as he walked off the mound and shared some choice words, prompting both benches to clear.

Kelly wasn't on the 2017 Dodgers, who lost the World Series to the Astros. But he was on a Red Sox team that lost to the Astros in the first round of that year's postseason and then beat them in the American League Championship Series the following year.

Kelly denied any intent with his pitches after the Dodgers' 5-2 victory, saying: "My accuracy isn't the best."

Astros manager Dusty Baker disagreed.

"Balls get away sometimes, but not that many in the big leagues," Baker said. "When you throw a 3-0 fastball over a guy's head, now you're flirting with ending his career."

Kelly was noticeably erratic in the bottom of the sixth. He fell behind 3-0 to Bregman before the fastball sailed on him. Bregman took his base without saying a word.

Two batters later, after the broadcast caught someone yelling at Kelly to "get back on the mound, little f---er," Kelly threw four consecutive pitches high against Astros first baseman Yuli Gurriel, one of them a curveball that nearly hit him.

The first two pitches to Correa, also curveballs, brushed him back

But then Kelly threw four more and ultimately struck out Correa on a breaking ball that tailed low and away, leaving two runners stranded and maintaining the Dodgers' three-run lead.

The two soon began jawing at one another, prompting both benches to clear with no punches thrown.

A warning was issued to both sides, and Astros manager Dusty Baker got into a close, heated conversation with crew chief Chris Guccione.

Baker said that after Kelly pursed his lips at Correa, he also yelled: "Nice swing, b----."

"What are you supposed to do then?" Baker said. "And what upset me was the umpires warned us. Why don't you warn him? He's the one throwing the ball. He's the one that started this mess in the first place. I didn't like it at all."

Kelly called his actions toward Correa an "in-the-moment-type thing" and said he didn't remember what he said.

On his facial contortions, which have become a popular GIF: "I guess my expression was what I interpreted in my head."

Tuesday's game marked the first time the Dodgers and Astros have met since the Astros were revealed to have illegally stolen signs and communicated them to their hitters by banging a trash can in 2017, a method that seemingly extended all the way through a seven-game World Series triumph over the Dodgers.

The Dodgers expressed a lot of public anger toward the Astros during spring training.