NEW YORK – The Twins probably weren't going to win anyway on Saturday, not with Tyler Mahle having difficulty throwing strikes, not with Kyle Higashioka clobbering a home run into the Twins bullpen and Anthony Rizzo blooping one just past the foul pole, not with the Yankees putting runners in scoring position in six of their eight turns at bat.

But some rosin found on Domingo Germán's right pinky made the Twins suspicious that their 6-1 loss in Yankee Stadium might not have been completely legitimate.

"I'm not saying he's doing anything bad," designated hitter Byron Buxton said after the most effective start of the back-of-the-rotation righthander's career. "But it's not a good look."

Germán struck out 10 of the first 14 Twins he faced and carried a perfect game into the sixth inning, a remarkable turnaround after two short-and-messy starts to his season. But his hands, not his pitches, were the center of a controversy that grew after the standard end-of-inning check for foreign substances as he left the mound in the third inning.

Crew chief James Hoye discovered Germán's pitching hand was unusually tacky and asked him if he was using rosin, which pitchers are allowed to use to get a better grip on the baseball as they pitch. "I said, 'I need you to clean it up,' " Hoye told a pool reporter after the game. When Germán came out to start the fourth inning, Hoye checked the pitcher's hand again, "and there was still some tackiness on his pinky. And I said, 'I just told you to clean this up.' "

The umpires huddled, with Germán's interpreter and New York manager Aaron Boone listening in, to discuss whether the pitcher was breaking baseball's rule against foreign substances. They finally determined he had not and allowed Germán to take the mound.

Twins manager Rocco Baldelli loudly objected — to the process, not the substance on Germán's hand.

"He was warned. He didn't fully comply with the warning, from what I was told, and was allowed to keep pitching," Baldelli complained. "I don't agree with that in principle."

He stated his case so persistently and vehemently, Hoye eventually ejected Baldelli, the outcome that the manager expected when he left the dugout.

"I wasn't going to go out on the field and return to the dugout, on principle, because I thought it was wrong," he said. "The pitcher didn't comply with what he was asked to do, and that upset me and upset everyone in our dugout. I can't go back in the dugout … and look everyone in the eye and say that's fine."

A lot of things weren't fine about the Twins' performance, which ended their four-game winning streak and set up a duel of aces — Pablo López vs. Gerrit Cole — on Sunday as the Twins try to win a four-game series in the Bronx for the first time since 1991.

And Germán, rosin or not, was the cause of most of them.

The 30-year-old Dominican, who entered the game with a 5.87 ERA this season, constantly worked from ahead in the count, throwing 16 first-pitch strikes to the 22 hitters he faced, and he recorded an amazing 18 swing-and-misses in his 6⅓ innings. He had no walks, one game after issuing a career-high five.

Not until Christian Vázquez lined a single with one out in the sixth inning did a Twins batter reach base. Germán departed after Trevor Larnach broke an 0-for-11 slump with a double into the right-field corner; Larnach scored the Twins' lone run when Jose Miranda doubled to left off reliever Michael King.

"He pitched well," Baldelli said of Germán. "I have no idea how to factor any of [the controversy] into how he pitched, I really don't."

Mahle, meanwhile, threw only eight first-pitch strikes to 21 hitters, and he walked three of them. The homers by Higashioka — which came after Mahle dropped a two-hopper to the mound that cost him an out — and Rizzo doomed his outing, but Mahle was working from behind all day.

"My slider was good, it had good movement, it was hard. I was just having trouble throwing it for strikes," said Mahle, who lasted only 4⅓ innings. "I was falling behind guys, and you can't do that because it gets the pitch count up there and you're kind of backed into a corner to throw some strikes if you're not getting ahead of guys. That's where I was at."