HOUSTON -- Astros starter Ronel Blanco was ejected at the start of the fourth inning of a 2-1 win over the Oakland Athletics on Tuesday night after umpires found a foreign substance that one called "the stickiest stuff I've felt on a glove."

Third base umpire Laz Diaz ejected Blanco after a check of his glove before he threw a pitch in the fourth inning. The umpires, Blanco and Houston manager Joe Espada stood at the mound for a couple of minutes discussing the issue before the right-hander was ejected.

Blanco's glove was confiscated, and first base umpire Erich Bacchus ran off the field with it and took it somewhere before returning. Diaz, who was the crew chief Tuesday, said it was being sent to the commissioner's office.

Bacchus said there was nothing on Blanco's glove when he checked it in the middle of the first inning, but he discovered it when he did his second check before the fourth.

"I felt something inside the glove," Bacchus said. "It was the stickiest stuff I've felt on a glove since we've been doing this for a few years now."

After Bacchus discovered the substance, he called the rest of the crew in to confer.

"Everybody checked the glove to make sure we all had the same thing and he had to get ejected because he had a foreign substance on his glove," Diaz said.

Diaz said they didn't know what the substance was.

"We don't determine that," he said. "We just felt it was sticky, sticky enough that our fingers got stuck. So now it's all up to the office on what it was and all that."

Blanco denied using an illegal substance.

"Just probably rosin I put on my left arm," he said in Spanish through an interpreter. "Maybe because of the sweat it got into the glove and that's maybe what they found."

Espada added that when he went to the mound he saw "white powder" inside Blanco's glove.

"It looked to me when I grabbed the glove [that] there was some rosin," Espada said. "You're not allowed to use rosin on your non-pitching hand, and that's what it looked like to me. It was a little bit sticky with the moisture and the sweat, but that's what it looked like to me."

Blanco held out his hands and patted them together in front of the umpires while they inspected his glove before he was ejected, and he did the motion again after he was tossed.

"What I told them is, 'If you found something sticky in my glove you should also check my hands because it should also be on my hand,'" Blanco said. "'Just check my hand,' and he didn't."

Blanco, who threw a no-hitter in his season debut, allowed four hits and struck out one in three scoreless innings Tuesday. He has a 2.09 ERA this season. The Astros led 1-0 when he was replaced by Tayler Scott.

MLB began cracking down on foreign substances in June 2021, and Blanco will likely face a 10-game suspension for the infraction.