CINCINNATI -- Marlins No. 4 prospect JJ Bleday made hard contact vs. the Reds all of Tuesday with nothing to show for it. He finally reaped the rewards on Wednesday night, hitting his first Major League home run in his second at-bat.

Bleday turned on Reds All-Star right-hander Luis Castillo’s knee-high changeup for a leadoff shot to right field in the fourth inning at Great American Ball Park. According to Baseball Savant, it would have been a homer in every ballpark except Coors Field.

While the 24-year-old Bleday appeared cool, casual and collected rounding the bases, he finally cracked a smile upon reaching the dugout and being greeted by coaches and teammates. After flying out sharply to the warning track during Tuesday’s 0-for-5 performance -- his first hitless showing since debuting on Saturday -- Bleday went deep in his 16th career plate appearance.

In his first matchup with Castillo, a former Marlins farmhand who is the top starting pitcher on the Trade Deadline market, Bleday fouled a 98.2 mph four-seamer straight back. On the next pitch, he struck out on an elevated 98 mph fastball.

“[JJ] just missed a couple, popped a couple up, and then hit two other ones kind of got on the nose a little too high,” manager Don Mattingly said pregame Wednesday. “I think his at-bats have been good. I think that's what I kind of watched more than anything is just him having an understanding, game planning. That part for me is advanced for a guy coming up. Even compared to some of our other young guys, he's got an advanced understanding of what he wants to do at the plate.”

Bleday, who turned heads in February with a bulked-up physique, has found his power stroke in 2022 after knocking just 12 for Double-A Pensacola in ‘21. Prior to his promotion, he collected 20 homers at Triple-A Jacksonville. Though his average was down (.229), he still had a high on-base percentage (.365) thanks to a good eye at the plate.

“I think the main key has been maintaining the weight, and that's just eating as much as you can and frequently,” Bleday told MLB.com on Monday. “You don't have to be doing anything crazy, but taking care of your body, drinking a lot of water, drinking a lot of fluids, and then just eating three to four meals a day with some shakes here and there. I just feel more grounded in the box. I feel like I filled out a little bit better. I just feel more like my natural self, and then just the recovery has been better. I just feel stronger.

“I think that kind of carries into just game planning and being prepared, being ready to hit and then just mechanically spitting out more consistent swings.”