OAKLAND -- Trent Grisham was golfing when he got the news. The former first-round Draft pick who went by Trent Clark when Milwaukee took him 15th overall in 2015, and who had grinded through several disappointing seasons before a swing change produced a breakout this year, was shocked to learn that he was being called up to the Major Leagues. He immediately contacted his mother, Michelle Grisham, whose influence prompted Trent’s name change in 2017.

What was her reaction?

“She started screaming,” Grisham said Thursday morning, only a few minutes after arriving at the Oakland Coliseum and seeing his name in the starting lineup for the Brewers’ series finale against the A’s, which the club lost, 5-3. “Then we started looking for flights right away.”

Mom was in the stands Thursday for her son’s unexpected Major League debut, which was prompted by a sensational showing this season at Double-A Biloxi and Triple-A San Antonio, capped by a career night Tuesday in which Grisham hit for the cycle with two home runs.

His OPS this season at the two stops was 1.010 with 26 home runs and 54 extra-base hits. The year before at Biloxi, Grisham had a .693 OPS with seven home runs and 19 extra-base hits in about 10 percent fewer at-bats. His surge pushed Grisham back up to sixth on MLB Pipeline’s list of Milwaukee’s top prospects.

The change? Grisham work in concert with the Brewers’ player development staff, a group that among others, included hitting coordinator Kenny Graham and three of Milwaukee’s Minor League hitting coaches -- Al LeBoeuf, Danny Santin and Dave Joppie -- to change his point of contact. Blessed with a keen batting eye, Grisham had long watched the baseball get as close as possible to the plate before beginning his swing. Now, he was making contact more out in front, and doing damage.

“With that, I started playing better and better and I just got more and more confidence,” Grisham said. “And now that’s really what I’m relying on -- confidence in myself and just going out there and playing.”

“This is a great story for the organization,” said Brewers hitting coach Andy Haines. “Preaching ‘collaboration’ and all of those clichés we use, this is what happens when you do it right.”

Brewers manager Craig Counsell called it a good lesson for everyone.

“This is a talented kid, and he’s still young,” Counsell said. “When you look at the finished product, everybody takes their own journey. It’s not always a smooth, upward climb and sometimes guys go in a different direction. But it’s Trent’s journey and it’s ended up in a really good place.”

Grisham hadn’t had a chance to let it sink in yet. He did not arrive at the ballpark until a little more than two hours before Thursday’s first pitch and scrambled through all of the first-day duties before starting in center field for the Brewers. With no batting practice before a day game, Grisham’s first swing on a Major League field was in the top of the second inning, when he lifted an 0-2 pitch from A’s starter Homer Bailey for a flyout to center field. Two innings later, Grisham hit a sacrifice fly to give the Brewers a 2-1 lead. He finished 0-for-3, but collected his first big league RBI.

“Day 1 in the big leagues, you’ve just got to get through it,” Counsell said.

Grisham’s family was there to go through it with him. His mother, his brother, a nephew and Grisham's fiancée, Megan, were in the stands.

“Ups and downs, for sure,” Grisham said of getting to this point. “But it’s been really exciting. Going into this last offseason, I really wanted to get better and figure out what was going on and kind of put some stuff together. I didn’t really have any expectations for this year -- just go play hard and see what happens, because I knew I was prepared. Then all this came out and I played really well and it’s just been building and building.”