"You've got to face whoever you're facing," said Gregorius, hitting a robust .368 (21-for-57) off lefties this year. "For me, it doesn't really matter who I'm facing, lefty or righty. You never really know how that guy's going to feel today. Whoever is on the mound, that's who we've got to be ready for."
It was the second three-run homer in three games for Gregorius, who also slugged a long ball in Tuesday's 13-10 loss to the Rockies at Coors Field. He is hitting .354 (17-for-48) over his last 12 contests, and the Yankees have been thrilled to see his development over the last year-plus.
"He's just more comfortable," said Yankees left-hander CC Sabathia, Thursday's winning pitcher. "He's a tremendous athlete and he makes pretty much every play. He makes every play. Just to see him relax and be able to go out and be able to have fun playing the game, I think it's made a huge difference."
In 2014 with the D-backs, Gregorius batted an anemic .137 (7-for-51) against lefties, but manager Joe Girardi believes that Gregorius gained confidence by playing more regularly.
"I think just seeing them, getting a chance to play against them," Girardi said. "We picked some spots last year to give him time off against lefties, and he kind of grew into it. He's had really good at-bats against lefties the second half of last year, and this year; it's a big difference for him."
Gregorius traces his improvement to the halfway point of last season, when he batted over .300 in July and August, then went into the offseason looking to continue that upward trend.
Mechanically, Gregorius said that he and hitting coach Alan Cockrell worked on keeping his front shoulder in as long as possible to avoid flying open.
"I think the second half of the season last year, that's when I kind of figured out everything hitting-wise," Gregorius said. "It's still working for me, so I don't really see why I have to change it. We've got to keep doing that in a positive way."
Bryan Hoch has covered the Yankees for MLB.com since 2007. Follow him on Twitter @bryanhoch, on Facebook and read his MLBlog, Bombers Beat. This story was not subject to the approval of Major League Baseball or its clubs.