BALTIMORE - A couple hours before his second go-around in Major League Baseball,Arvin Roberts Jackson Holliday expressed hopes that it will be less of a blur this time around, that he'd be able to enjoy it and "be present" after a rough debut in April.

A few hours later, Holliday slowed things down plenty, driving a slider 439 feet for his first major league home run. 

A grand slam, no less. 

Holliday's first of what's expected to be many round-trippers came with the bases loaded in the fifth inning Wednesday afternoon at Camden Yards, off Toronto Blue Jays reliever Yerry Rodriguez. It cleared the flag court and landed on Eutaw Street, where a brick will commemorate the blast alongside the dozens of other big league sluggers with that kind of pop. 

After Holliday ran the bases and slapped hands with Ryan Mountcastle, Cedric Mullins and Jordan Westburg at home plate, many in the Camden Yards crowd of 25,528 stayed on their feet. In the Orioles dugout, reigning Rookie of the Year Gunnar Henderson pointed to the field - guiding Holliday to his first career curtain call. 

All things Orioles: Latest Baltimore Orioles news, schedule, roster, stats, injury updates and more.

Holliday, 20, became the youngest player in Orioles history to hit a grand slam and just the third to hit his first homer with the bases loaded.

"It’s pretty surreal. Can’t have dreamed it up much better for a first home run," says Holliday. "That’s about as best as I can hit a ball."

It was a key step in the arc of baseball's top prospect, who debuted in April but proceeded to go 2 for 34 with 18 strikeouts, earning him a trip to Class AAA Norfolk. Holliday expressed confidence Wednesday that the 346 additional minor league plate appearances would serve him well in, what he called, "the world's toughest league."

Three at-bats into that stint, he proved the hard work had paid off. And no matter how many home runs he hits, it will be tough to match the thunder of his first.

The Orioles will need Holliday's production even more than they'd imagined. Westburg, their All-Star infielder, suffered a right hand fracture when he was hit by a Rodriguez pitch preceding Holliday's slam. Manager Brandon Hyde indicated Westburg would be out until roughly the end of the regular season.