Four pitches later, Rodriguez was trotting the bases after sending a 2-1 slider from Reds starter Johnny Cueto 416 feet over the wall in left-center field.
"I was just trying to see the ball and hit the ball," Rodriguez said after San Diego's 9-4 loss to Cincinnati. "I was trying to just make sure I give it a good at-bat and when the result came, I can't explain it. I still get goosebumps. It was unbelievable."
Rodriguez became the second player this season to hit a home run in his first career at-bat, joining the Pirates' Starling Marte, who accomplished the feat on July 26.
Cueto had only allowed five home runs in 22 starts all season to that point. He hadn't allowed a homer since May 25, marking 11 starts and 80 innings that he kept the ball in the park.
Rodriguez snapped that streak in his first day in a Padres uniform.
"Isn't that great?" said San Diego manager Bud Black. "First Major League at-bat, he hits a home run off Johnny Cueto. That's a day that he'll never forget, and I'm sure a lot of us won't forget. That's why you come to the ballpark, because you're going to see something possibly like that happen on any given day."
Aside from just being a rookie and making a splash in his debut, Rodriguez's story gets better and better the more oe delves into it.
Rodriguez grew up in Villa Clara, Cuba, with his family. Before his baseball days, Rodriguez and his family were defected from Cuba, and after a whirlwind of struggles, landed in Miami.
Rodriguez received a scholarship from the University of Miami before being drafted by the Reds in 2006.
He spent three seasons in the Reds' farm system before being released in 2008. The 26-year-old joined the Independent League for two more seasons before finally being picked up by the Padres last year.
"I came up with Johnny through the Reds. It just makes this moment more gratifying," Rodriguez said. "It's been a long road, I've always had my family and my mom behind me 100 percent of the time, so it makes things a lot easier. Independent ball ... you're trying to get a chance to play in the Major Leagues and play in front of fans. I was very blessed to get that call that I was coming here."
Just two days ago, Rodriguez was hitting .223 in Class A Lake Elsinore.
When Yasmani Grandal, a fellow rookie, was placed on the 15-day disabled list Tuesday for a strained muscle, Rodriguez got his call.
"Unfortunately, injuries are part of baseball," Rodriguez said. "You never want to get here in that way, but it's part of the game, and I'm just here to help the team win. [Grandal] is a huge part of this team and is a very pivotal part of the San Diego Padres as an organization moving forward. I'm just here to do my job and take it day to day."
This is where things start to get even crazier.
Grandal was also a former Draft pick of the Reds back in 2010. He attended the University of Miami where he played catcher after Rodriguez's departure. And his first Major League hit, while it wasn't in his first at-bat, was also a home run.
"We've known each other since I was probably a junior in college and he was a senior in high school," Rodriguez said. "The University of Miami family is pretty close. All the baseball players, we keep in contact and it's a very tight-knit family that we have down there."
Even closer than his college family is Rodriguez's immediate family, which was the No. 1 thing on his mind following his big day on the diamond.
"All I could think about was all the hard work. I just thought of my mom," said Rodriguez, choking up as he reminisced on his family's struggles.
After the home run, Reds fans tossed the ball back onto the field.
Whether it was a good-natured move or a competitive jab, Rodriguez doesn't care. If the ball makes its way back to Rodriguez's hand, he already knows exactly what he'll do with it.
"I'm going to put it in a box and send it to my mom," he said.