Marrero was the 24th overall pick, going 41 selections ahead of Pedroia back in 2004.
Listed at 6-foot-1 and 194 pounds, Marrero is 21 years old.
He is considered a plus-defender with good bat speed and the ability to put the ball in the gaps. There is a chance Marrero will develop power as he continues to grow.
"We look forward to trying to get him into the Red Sox organization," said general manager Ben Cherington. "He's a talented shortstop who's been a good player at a major program and a good player at Team USA and a guy we liked a lot coming into the spring and like a lot moving forward."
Some draft boards had Marrero going in the Top 10, so the Red Sox gladly scooped him up late in the first round.
"We weren't sure [if he would be there] as the draft evolved," said Cherington. "He was still on the board as we got close to our pick, so we started thinking it was a possibility. There were a couple of teams we thought might be a spot where he'd go, and he didn't. We were happy he got there."
Marrero had been on Boston's radar for a while, back to his days at American Heritage High School in Plantation, Fla., where he teamed with current Major Leaguer Eric Hosmer.
"We saw a lot of him as a junior in high school," said director of amateur scouting Amiel Sawdaye. "He was on the same team as Eric Hosmer, so history-wise, we probably had as much comfort with him as we had with any player in this Draft. It's a big-time program we see every year with ASU."
The reason Marrero likely slipped is because his offensive numbers were a little underwhelming in his junior season. Marrero hit .284 with a .340 on-base percentage, a .436 slugging percentage and four homers.
"I didn't actually [think] the offensive decline was as much of a worry for us," Sawdaye. "He showed us some things in the box that we really liked and some things that we really look for. Certainly, I think he expected to have a better year statistically, but it's not something that is a concern for us either from injury or physical play."
Boston had far more looks at Marrero's bat than what he did for ASU in 2012.
"We've gotten a chance to get to know him and spend some time with him on the Cape. We saw him with a wood bat the last two summers," said Sawdaye. "He has a very quiet swing -- functional. He's a guy that sprays the ball around the field. He has what we call sneaky power -- a guy that obviously doesn't look like the biggest player on the field but can definitely juice the ball out of the stadium. He's certainly somebody who we feel like has a chance to impact the baseball."
While the Red Sox also drafted Pedroia as a shortstop eight years ago before he turned into an elite second baseman, the club has no current plans to move Marrero.
His defense has drawn high marks across the board.
"We think he's advanced on both sides of the baseball. Certainly, I think he's probably a better defender," said Sawdaye. "We don't see him moving off shortstop. We think he's a guy that in the long term is going to be a shortstop. I don't think the question of moving him to a different position is even one we're going to tackle right now."