When Clint Frazier stepped to the plate in the bottom of the ninth inning on Saturday, with two men on base and the Yankees trailing the Milwaukee Brewers by a run, his goals were decidedly modest.

“Just try to get a fastball down the middle,” Frazier said, “something I could drive back up the middle to at least advance the runners over one base.

“I was really amped up. I wanted to make sure I didn’t go up there and take a really big swing.”

There were several reasons for Frazier’s self-restraint: He was making just his sixth start in the major leagues, and this would be only his 20th major league at-bat. After batting three times against Brewers starter Brent Suter, who never hit 90 miles per hour with his fastball, he was now facing closer Corey Knebel, who routinely hits 99.

And besides, Frazier was all of one day into learning a new swing.

On Friday, the Yankees’ hitting coaches, Marcus Thames and Alan Cockrell, had called Frazier’s attention to a “hitch” in his swing, a tiny hesitation that was messing up his timing and causing him to jump at the baseball. After the flaw was pointed out, Frazier put himself through a crash course over the next 24 hours, taking what he estimated to be 300 swings and wearing out two pairs of batting gloves.