A power-hitting third baseman for Miami's Monsignor Pace High, Marrero hit 13 home runs this season to lead his team to the Class 4A state title. The guy playing next to him, Pace shortstop Adrian Cardenas, has produced a Miami-Dade County-tying record 18.
Cardenas, who has come on to be likely chosen anywhere from the late first to the third round, has taken "some of the shine off" Marrero's stature among the nation's high school players, according to one scout. Yet Marrero still could be a top 10 pick amid an abundance of touted collegiate pitchers.
In particular, the Orioles, at No. 9, are known to have some interest in him.
Never mind that Cardenas hit .630 this season to Marrero's .375, with 28 more RBIs and six more home runs. Marrero has been followed by scouts since his freshman year, so they likely have a rating on his potential that depends very little, if at all, on his latest statistics.
"A couple of clubs are probably happy to see the year he had, so other people would pull off of him and he would be more available to them," said Tom Duffin, the Pace High coach.
At 6-foot-3 and a muscular 215 pounds, with a bazooka-like arm, Marrero reminds some of a young Alex Rodriguez, who attended high school at the other end of town, at Westminster Christian. Rodriguez remains the only Miami player to be taken as the No. 1 overall pick in the draft.
"He has a strong arm, athletic ability and physically he is right where he needs to be," said Bill Henderson, the coach at Westminster Christian, of Marrero. "So he's got all the physical tools."
Henderson only got to see Marrero once this year -- when Pace whipped his team, 12-0. Henderson looked on in amazement as Marrero hit a home run he estimated to travel 450 feet.
Because Henderson doesn't know Marrero, he said he could not venture an opinion on the youngster's mental toughness and desire to succeed. In his frame of reference as the Detroit Tigers' No. 1 pick in 1987, Henderson puts heavy weight on those intangibles because he looks back on a potential Major League career that was, in part, sidetracked by them.
Duffin said the 18-year-old Marrero, who hit .430 with eight home runs as a junior, is certainly mentally tough enough to handle a professional career, and his desire to succeed is unquestioned.
"The kid has handled the pressure of not doing as well as everybody anticipated," Duffin said. "I've never seen the kid crack. I haven't seen him throw tantrums or anything like that. He's had a real professional attitude. I've brought him to the side and had a conversation with him about the way things have gone. I know it's eating him up, but he's kept his poise."
Duffin said Marrero -- no relation to the Colorado Rockies' Eli Marrero, who attended Coral Gables (Fla.) High -- has been dogged by upwards of 15 scouts every time he takes batting practice or plays in a game for several years now. "That's a lot to put on a kid."
That's one reason Marrero is looking forward to the draft.
"You learn to deal with it, but sometimes it does get a little old," he said. "I'd be in class sometimes and get calls from scouts asking me when I was going to hit or asking to come to my house."
Marrero, after all, is a veteran of all-star games that have drawn many of the nation's top draft prospects. He missed several games last summer -- USA Baseball's Tournament of Stars in Joplin, Mo., and the East Coast Showcase in Wilmington, N.C. -- because of a strained hamstring. Coming back for the AFLAC All-American Classic in Baltimore late in the summer, he went 1-for-4 with two RBIs.
Duffin said Marrero has a "great" arm and good hands and speed for a big guy. Yet his most distinctive asset may be his power. Duffin said the only South Florida high schooler he's ever seen that may compare with Marrero in power is Ryan Shealy, a 6-foot-5, 250-pounder who's now a first baseman on the Rockies' 40-man roster.
"When he hits it, it can go a very long way," Duffin said. "The kid has awesome power."
Marrero, who has been hitting in a batting cage behind his family's home since he was 7, said he's been working particularly hard the last two years to get to the point where he is now, as a high draft pick. He's also been told it's likely to pay off.
"I talked to a scout the other day who told me, 'The draft is going to treat you good.'"
Charlie Nobles is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.