"I accept it," Pineda said before Thursday night's game at Fenway Park. "I know I made a mistake."
The commissioner's office announced the ban, which started immediately.
Pineda was ejected in the second inning of Wednesday night's 5-1 loss to the Boston Red Sox after umpires found the pine tar on the right side of the right-hander's neck.
After the game, Pineda admitted he used the pine tar to help him grip the ball on a cool, windy night.
"I feel so bad," he said Thursday.
Pineda said he had never used pine tar before this season. He spent his first season in the majors with the Seattle Mariners in 2011 then missed the last two with the Yankees following right shoulder surgery.
"I think he understood" the seriousness of his action, said Yankees manager Joe Girardi, who expected a suspension of about 10 games, "but I think he got caught up in the moment of competing and it got the best of him."
Girardi indicated David Phelps would take Pineda's turn in the rotation. Phelps came into the game with two outs in the second after Pineda was ejected.
The ejection set off a debate in the baseball world about pitchers who try pine tar, and whether it should be allowed in certain circumstances. Many former aces said they had done it, albeit in a more discreet manner.
"I've seen a lot of things in my career, so I'm not blind to it" being viewed as part of baseball, said Girardi, a former catcher in his seventh year as Yankees manager.
Rule 8.02(b) prohibits pitchers from altering the ball to gain an unfair advantage, and forbids them from having a foreign substance on them or in their possession on the mound.
"I wouldn't be against coming up with an idea" to modify the rule so pitchers could get a better grip on the ball in cold weather, Girardi said. "It would be a great time for someone to start looking at" coming up with one substance pitchers would be allowed to use.
Pineda wasn't seen with the pine tar in the first inning, when the Red Sox roughed him up. Boston manager John Farrell asked plate umpire Gerry Davis to check Pineda after two fast outs the next inning.
Davis went to the mound, touched Pineda's neck and ejected him.
Earlier this month, Pineda pitched well in a 4-1 win over the Red Sox at Yankee Stadium. Television cameras showed a substance on his hand in the fourth inning - Pineda said it was dirt, not pine tar. His hand was clean in the fifth and Farrell didn't ask for him to be checked.
Pineda said he didn't use pine tar in a start against the Chicago Cubs, in between his Red Sox outings.
Among other suspensions of pitchers for pine tar in the past decade, Tampa Bay's Joel Peralta was penalized eight games in 2012, the Angels' Brendan Donnelly 10 days in 2005 and St. Louis' Julian Tavarez 10 days in 2004. The suspensions of Donnelly and Tavarez were cut to eight days after they asked the players' association to appeal, and Peralta dropped his challenge with no reduction.
Pineda said Thursday he didn't feel the ball well in the first inning when he allowed two runs on four hits. And he said he wanted to be careful not to hit any batters.
"I know it's pine tar, but the pine tar did not help me" throw harder, he said. "It helped me for feel, (get) a better grip."
He also said no one told him to use it. He said he did it "by myself."