One of the unique aspects of 2021 Spring Training is that many organizations, the Mets included, invited their top prospects -- no matter how young -- to get them experience following a lost Minor League season. Because so many of the Mets’ Top 30 prospects last played at the low levels of the Minors, that meant an infusion of 19-, 20-, and 21-year-olds to big league Spring Training.

• Mets' Top 30 prospects | Breaking down the list

In the Mets’ case, it meant that eight of their Top 10 prospects have been in Port St. Lucie, Fla., for weeks. Here’s something on each of them who made the cut:

No. 1: C Francisco Alvarez
The most significant question surrounding Alvarez is one he won’t be able to answer this month. While the Mets invited the 19-year-old to big league camp to give him experience in the clubhouse and against high-level pitching, they didn’t use him behind the plate in Grapefruit League games. Instead, Alvarez took a few at-bats at designated hitter. Generally speaking, the scouting community doesn’t doubt Alvarez’s ability to hit. It’s his ability to stick behind the plate that could make the difference between an average player and a superstar.

No. 2: SS Ronny Mauricio
Similar to Alvarez, Mauricio’s position remains a question, though the situation in his case is different. Although the Mets intend to keep developing Mauricio as a shortstop, that could change if the team signs Francisco Lindor to a long-term extension. Already, the 19-year-old has demonstrated a willingness to switch positions, saying he’d feel comfortable trying out second or third. Given how much muscle mass Mauricio has gained over the past few years, third might become his ultimate destination, anyway.

“We haven’t had those conversations,” manager Luis Rojas said this week. “I always think that versatility is a strength, especially at a young age, just because it will open the door for you to come and join the big league club at any time, and it won’t limit you. … I’m glad that he has the open mind. I think that’s a strength.”

No. 3: RHP Matthew Allan
Allan has found an ideal mentor in Jacob deGrom, who began tutoring the hard-throwing youngster last summer in Florida. Before the Mets cut Allan from big league camp, they used him for an inning of a Grapefruit League game against the Nationals. The former third-round Draft pick didn’t disappoint, dialing his fastball up to 97 mph. Afterward, Rojas lauded the 19-year-old Allan for his poise.

“Nineteen?” the manager said. “He definitely behaves like an older person.”

No. 4: 3B Brett Baty
Asked about his sweet left-handed swing, Baty -- the Mets’ first-round pick in 2019 -- named Freddie Freeman and Adam Dunn as players he tends to emulate. Baty’s relative lack of prospect hype may be due to the fact that he’s ranked behind Allan, a third-rounder in his Draft class who might have been a first-rounder if not for signability concerns. The Mets are happy to have them both, and the 21-year-old Baty renewed their faith early in camp with a pair of opposite-field hits.

No. 5: OF Pete Crow-Armstrong
The Mets’ years-long struggle to find an everyday center fielder could end with Crow-Armstrong, who is nothing if not athletic. Crow-Armstrong proved that much with a frantic triple early in Grapefruit League play, which also showcased his ability to make loud contact. But the 18-year-old’s calling card is his defense.

The Mets haven’t had a true, reliable center fielder since Carlos Beltrán. (They thought Juan Lagares might fill the role, but he never turned into the type of player they expected; similarly, defensive questions continue to dog Brandon Nimmo.) Crow-Armstrong, who went to the same California high school as Lucas Giolito, Jack Flaherty and Max Fried, could change that narrative.

“I just hope I make a good impression on people,” Crow-Armstrong said.

No. 6: RHP J.T. Ginn
Ginn underwent Tommy John surgery just before Noah Syndergaard last March. The Mets took a risk on drafting him in the second round anyway and now are treading carefully with Ginn, who trained with Syndergaard this winter in Florida and is a bit behind him in his rehab. The team has no reason to rush Ginn, another first-round talent who fell in the Draft. The right-hander figures to be on strict workload restrictions in his first season of pro ball, but he’ll be 22 this year with a chance to rise quickly through the system once he’s healthy.

No. 7: OF Khalil Lee
Although Lee has scuffled both offensively and defensively in his first camp with the Mets, there’s plenty of room for the 22-year-old outfielder to grow. When the Mets acquired Lee from the Royals as part of a three-team trade with the Red Sox, they never actually negotiated directly with Kansas City officials. Mets general manager Zack Scott instead used his old Boston contacts, who knew how much he coveted the player.

No. 8: 3B Mark Vientos
When Rojas laid eyes on Vientos this spring, he marveled that the third baseman “is turning into a man right now.” That’s notable. When the Mets selected Vientos as a 17-year-old back in 2017, he was the youngest player in the Draft. At 21, he’s now old compared to fellow top prospects Alvarez, Mauricio and Allan, which also means there’s room for the Mets to promote Vientos aggressively over the next year or two.

“It does make me feel a little old,” Vientos said, laughing. “But being around Brett, Pete, all these talented young players is a great experience.”