The New York Mets added a new key voice to Andy Green's coaching staff on Monday, hiring Mariano Duncan, according to Joel Sherman of the New York Post.

While Duncan's exact role remains unclear, Sherman reported that he's expected to work with players in several different areas.

Duncan, 63, played 12 seasons in the major leagues, winning a World Series with both the New York Yankees and Cincinnati Reds. Since his playing days ended, he has held coaching positions with several organizations at both the major and minor league levels.

Most recently, Duncan spent the past five seasons as the bench coach for the Mets' Double-A affiliate, Binghamton Rumble Ponies, overseeing a crop of prospects who have since established themselves in New York.

While hiring a new coach who isn't specifically responsible for hitting or pitching may not seem like a major move, it still can have a significant impact on players.

Here are three in particular who could benefit the most from Duncan's arrival.

1. Francisco Alvarez

It's sometimes easy to forget that Francisco Alvarez is only 24 years old after already appearing in parts of five major league seasons. And while he hasn't quite lived up to the expectations that came with being a former top prospect, his age offers hope that he can still become the player many once envisioned.

Perhaps Duncan's presence could help unlock that potential.

Duncan worked with Alvarez during his time at High-A Brooklyn and Double-A Binghamton between 2021 and 2022, when the young catcher was at his peak as a prospect. Over 151 games between both levels, Alvarez slugged a combined 40 home runs.

However, Alvarez's transition to the major leagues hasn't been nearly as smooth, as he's struggled to find a consistent approach at the plate.

When Alvarez first arrived in the majors, he was overly aggressive, often swinging for the fences and looking to pull the ball. He then learned to spray the ball to the opposite field but became too focused on that approach, seemingly losing sight of what made him a promising hitter in the first place.

Last season, he appeared caught between those two approaches, struggling to establish a clear identity as a hitter.

At his age, Alvarez is still impressionable, and a familiar voice offering a different perspective could make a big difference. Perhaps someone like Duncan, who has seen Alvarez at his best, can help him finally become the player the Mets always believed he could be.

2. Brett Baty

Just as Alvarez was thriving at Double-A Binghamton, so was Brett Baty.

In 89 games at Binghamton in 2022, Baty hit .312 with 19 home runs and a .950 OPS. At the time, Baty was displaying all the tools that once made him one of baseball's top prospects. He was lauded for his ability to spray the ball all around the field with authority, regardless of where he was pitched.

While that success hasn't consistently translated to the major league level, Baty has shown flashes of the same ability throughout his short career. Most recently, he hit .303 with five home runs and a .926 OPS over his last 40 games of the regular season.

Translating that success into a full season remains a serious question mark. As David Stearns has indicated, the Mets can't commit to Baty until he proves he can sustain that production.

Entering his age-27 season, Baty has reached a pivotal point in his career. The Mets would love nothing more than for him to combine his defensive versatility with consistent offensive production.

Perhaps Duncan, having witnessed Baty's success firsthand in the minor leagues, can help him build on his recent progress and finally establish himself as a consistent major league hitter.

3. Jefferson Rojas

One more player who may stand to benefit from Duncan's arrival is Jefferson Rojas, who will likely make his major league debut next season.

The 21-year-old appeared in just 29 games with Double-A Binghamton after the Mets acquired him, but it didn't take long for Rojas to show why he was so highly touted. In 118 at-bats, Rojas hit .280 with eight doubles and nine home runs.

For such a young player, the transition from the minor leagues to the majors can be daunting, as both Alvarez and Baty can attest. Having someone familiar to help guide Rojas through such a significant adjustment could prove invaluable.

Rojas and Duncan are also both natives of the Dominican Republic, potentially providing another source of familiarity for the prized prospect as he enters a new environment.

Duncan was an infielder during his major league career, primarily playing second base, where Rojas figures to receive opportunities next season.

Having both a fellow countryman and a former All-Star with experience at his position could make Duncan an especially valuable mentor for Rojas as he begins his major league career.