On Thursday, Marrero's journey to Fenway will truly begin, when he reports to the Class A Lowell Spinners.
"It hit me when I signed that dotted line. It hit me then that it was official," said Marrero, who's 6-foot-1 and grew up in Florida. "In the locker room, seeing all the guys, and then walking out here and doing all the stuff, this is real now. I get to start my dream, and I can't wait."
University of Florida left-handed pitcher Brian Johnson, the team's other first-rounder seven picks after Marrero at No. 31 overall, is expected to sign by the weekend at pick value, $1.575 million, a source said. Johnson should be coming to Boston soon for a physical now that Florida has been knocked out of the College World Series.
The Red Sox drafted Marrero, 21, out of Arizona State, the same college that produced the second baseman who could end up being his double-play partner someday, Dustin Pedroia. Marrero produced a .325 average (193-for-593) with 37 doubles, 11 triples, 12 homers, 95 RBIs and 102 runs in 150 games over three seasons with the Sun Devils.
Pedroia finished his ASU career with a .384 average (298-for-777).
"I'm trying to one-up him a little bit -- any way I can," Marrero said. "He's a great player, and that's one guy I can definitely follow."
Said Pedroia: "He's a great player, he's young, he's an exciting player, so it was pretty cool to see him in uniform."
Marrero's agent, Scott Boras, was on hand Wednesday.
"They both went to the same college, their style of thinking, their aggressiveness, team play, winning -- they're all of the same ilk," Boras said. "It's very nice for Deven that he gets to play with someone I think he admires and has a lot of the qualities that Deven aspires to have."
Marrero grew up a Marlins fan, a coincidence during the Marlins' visit to Fenway Park for a three-game series. He had been to Fenway before, with the Team USA collegiate team in 2011, but that pales in comparison to Wednesday's experience.
During batting practice, Marrero had no problem reaching the Green Monster.
"It's awesome. I peppered it a little bit," Marrero said. "It's kind of close, so I like that It was good hitting that thing and hearing that noise. I hit some out, so that was cool."
Marrero described himself as a two-hole hitter, going gap-to-gap and using his speed.
The pick value for Marrero's pick in the draft, No. 24, was $1.75 million, and his $2.05 million brings him in slightly over.
The Sox look like they'll steer clear of losing any future Draft picks because they spent too much in the first 10 rounds. The Sox should come in with less than 5 percent beyond pick value spent, preventing any forfeiture.
Three picks from the top 10 rounds remain unsigned: Johnson; third-rounder Austin Maddox (right-hander); and 10th-rounder J.T. Watkins (catcher). Maddox and Watkins are both expected to take below pick value, and Johnson will be signed at pick value.
The Sox also made official Wednesday the signing of sixth-rounder Justin Haley (Fresno State) and center fielder Iseha Conklin, a 19th-rounder out of Iowa Western Community College. The Red Sox have signed 14 of their 2012 Draft picks.
Evan Drellich is a reporter for MLB.com. Follow him on Twitter @EvanDrellich. Jonathan Mayo is a reporter for MLB.com and writes a blog, B3. Follow @JonathanMayoB3 on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.