NEW YORK -- The television cameras zoomed in for a closer look at Michael Pineda's right hand, and that led to widespread speculation on social media during the middle innings of Thursday's game between the Yankees and the Red Sox at Yankee Stadium.

A shiny substance was spotted on the hurler's right hand during the third inning of the Yankees' 4-1 victory, which went into the books as Pineda's first Major League win since 2011.

Pineda responded to the accusation by saying that it was only dirt. Many in the viewing audience raced to Twitter to share their own opinions.

"I don't use pine tar," Pineda insisted. "It's dirt. I'm sweating on my hand too much in-between innings."

Red Sox manager John Farrell said that he became aware of the issue during the fourth inning, and he said that the substance had vanished when Pineda returned to the mound to warm up for the top of the fifth.

Farrell suggested that the substance may have helped Pineda control the baseball on an evening when the first-pitch temperature was recorded at 54 degrees.

"Well, in the cold weather, you're trying to get a grip," Farrell said. "I can't say it's uncommon that guys would look to create a little bit of a grip. Typically, you're not trying to be as blatant."

According to rule 8.02.4 in the Major League Baseball official rulebook, "The pitcher shall not apply a foreign substance of any kind to the ball." A violation warrants an immediate ejection.

"The umpires did not observe an application of a foreign substance during the game, and the issue was not raised by the Red Sox," said Major League Baseball spokesperson Pat Courtney. "Given those circumstances, there are no plans to issue a suspension, but we intend to talk to the Yankees regarding what occurred."

Crew chief Brian O'Nora, who worked third base during Thursday's game, told a pool reporter that the umpires were not notified of an issue regarding a substance on Pineda's hand.

"I can't comment on it because we're on the field, and the Red Sox didn't bring it to our attention, so there's nothing we can do about it," O'Nora said. "If they bring it to our attention, then you've got to do something, but they didn't bring it to our attention."

In his postgame news conference, Yankees manager Joe Girardi lauded Pineda's seven-strikeout performance, and he made it clear that he did not wish to discuss the situation.

"There's really not much for me to speak on concerning that," Girardi said. "All I know is, he pitched extremely well and we're glad to have him back. ... I never saw it. There's nothing really for me to talk about."

The Red Sox have had their own recent history with pitchers and substances on the mound. Clay Buchholz, who took the loss Thursday, was accused of throwing spitballs in a start against the Blue Jays last May, and during the World Series against the Cardinals, Jon Lester's glove showed a green substance that was said to be resin.

Buchholz said after Thursday's game that a sticky substance like pine tar would improve a pitcher's control. He opined that teams would react more vehemently if an opponent was gaining an advantage by scuffing or otherwise doctoring the ball, rather than just trying to control pitches.

"Especially cold, windy nights, it's tough to get a grip on a baseball," Buchholz said. "I had that instance last year in Toronto about having stuff all over my body. You can use resin, water, the whole sunscreen stuff, whatever.

"It's either have a grip on a baseball and semi-know where it's going, or don't have a grip at all and get somebody hurt. How hard he was throwing early in the game, nobody wants to get hit by that, especially up around the head. So I don't think there'd be any organization that would want to do anything about it."

Along those lines, Pineda said that "nobody asked" him about the substance on his right hand. Asked to explain why it disappeared after the third inning, Pineda said, "I don't know. I usually put the dirt between innings when my hand gets sweaty."

Red Sox second baseman Dustin Pedroia said that it should be a "non-issue," pointing out that hitters always have pine tar on their bats. Designated hitter David Ortiz added that the substance, whatever it was, was not nearly as much of a concern for the Red Sox as Pineda's mid-90s velocity and biting slider.

"What happened? What was it?" Ortiz said. "Everybody uses pine tar in the league. It's not a big deal."