"First one in a Marlins [uniform], it felt good," Brinson said. "He was tough. Flaherty has good stuff, and he had it working today. I was trying to look for something up, and he was staying down in the zone real good with all of us. … That felt good, yeah."
Until the drive carried in the direction of the Marlins' clubhouse, Miami had been hitless off Flaherty, ranked as St. Louis' No. 2 prospect by MLB Pipeline.
Brinson is ranked by MLB Pipeline as the Marlins' No. 1 prospect, and 27th on Pipeline's Top 100 list. Flaherty ranks 38th.
"Power is part of my game, obviously," Brinson said. "I try to work in the cage on being an all-around hitter. I don't want to be a guy who just swings all-for-nothing, with a bunch of strikeouts. I don't like striking out. I can't help the team if I'm walking back to the bench, not putting the ball in play."
Acquired from the Brewers in the Christian Yelich trade, Brinson is competing for a roster spot.
Brinson certainly has power potential, and he showed it with his no-doubt home run to left, which had Marcell Ozuna looking up in the direction of the Marlins' building over the left-field stands.
"Obviously, I like to see him hit the ball out of the ballpark," manager Don Mattingly said. "But I like the adjustment. Facing the same guy, he looked really bad, and the next time up, we see that."
Camp battle Take your pick: Dan Straily or Jose Urena.
Either one will be the Marlins' Opening Day starter, and whoever doesn't get the nod will go in the second game. Mattingly shed that much light on how the top of his rotation will look when the season opens on March 29 against the Cubs at Marlins Park.
"I like either/or, it's one-two, two-one," Mattingly said about who will pitch the opener.
Urena and Straily or Straily and Urena are thus far the only locks in the Marlins' rotation, and both are lined up -- based on days off -- to pitch when the season opens with a four-game series against Chicago on March 29.
Cubs manager Joe Maddon has already set his rotation for the series at Marlins Park -- Jon Lester, Kyle Hendricks, Yu Darvish and Jose Quintana.
No matter who gets the Opening Day nod for Miami, Mattingly is hopeful Straily and Urena show durability and productivity over a long season.
"You're hoping for more than 30 starts from those guys," Mattingly said. "You're going to get the same team, and you're going to get the same teams next time for the most part. It's not like you're matching up anything."
Injury report Brett Graves exited Tuesday's game after 25 pitches in the first inning due to a left oblique strain. The right-hander is a Rule 5 Draft pick from the A's system. The Marlins listed him as day-to-day.
"I've never dealt with an oblique or anything like this," Graves said. "I have no idea what to expect. You kind of take it one day at a time and see how it responds tomorrow."
• Third baseman Martin Prado (right knee) and shortstop JT Riddle (left shoulder) took live batting practice on Tuesday morning. They faced Brad Ziegler, who will make his Grapefruit League debut on Thursday. Nick Wittgren (right elbow) was also encouraged when facing Prado and Riddle, and he expects to be ready for Opening Day.
Quotable "Jumbo is a guy, obviously, it's easy to remember his name." -- Mattingly, on reliever Jumbo Diaz, who received chants of "Jumbo! Jumbo!" after his one inning of relief
Up next The Marlins vist the Astros on Wednesday for a 1:05 p.m. ET Grapefruit League contest, available live via exclusive webcast on MLB.com. Lefty Justin Nicolino, in the mix for a rotation spot, will make the start. Prospects Nick Neidert and Pablo Lopez also are scheduled to pitch. Among the position players making the trip are Brinson and outfielder Magneuris Sierra. Starlin Castro and Justin Bour also are on the trip and are expected to appear in the lineup. Gerrit Cole will start for the Astros.