Boston Red Sox Breakout MLB Prospects Entering 2024


Entering 2024, we’re examining multiple Red Sox prospects on the verge of a breakout season. To qualify as a breakout prospect for this exercise, a player must rank outside the Top 10 Prospects in his organization entering the year.

You can find all of our preseason prospect rankings here and a link to breakouts for all 30 teams here.

Red Sox Top Prospects In 2024

We rank the top players in Boston’s system entering the season complete with new scouting reports, tools, grades & more.

Breakout Prospects

Allan Castro, OF

Preseason rank: 17
BA Grade: 45. Risk: High.

Track Record: The Red Sox signed Castro as a middle infielder in 2018, impressed with his athleticism and offensive potential in tryouts, with quick bat speed and the ability to manipulate the barrel from both sides of the plate. He proved a bit stiff to stay on the dirt in pro ball but quickly took to the outfield, where he could move more freely. After a solid 2022 season, Castro turned heads in spring training in 2023 with strength gains and increasingly loud contact. The strong first impression carried through a season when he hit .261/.368/.405 with a 14% walk rate and 18% strikeout rate at Low-A Salem and High-A Greenville. 

Scouting Report: Though a natural righthanded hitter, Castro has made enough strides as a lefthanded hitter–with simple, clean stances–to project as a solid line-drive hitter against righthanders in the big leagues. He’s currently more of a gap-to-gap hitter with solid plate discipline than a power hitter, though he does hit the ball hard enough to create more potential impact. That’s a step that is necessary for him to emerge as an everyday player. Castro moves well enough in the outfield to handle both corners while also offering an option in center, and he possesses the arm to handle any outfield spot. 

The Future: Castro likely will open 2024 in High-A, with a strong likelihood of moving to Double-A during the season. His solid, well-rounded skill set gives him a chance to be at least a fourth outfielder with a chance to improve that projection if he develops more power.

Scouting Grades
Hitting: 50. Power: 40. Run: 50. Fielding: 50. Arm: 55.

Yordanny Monegro, RHP

Preseason rank: 18
BA Grade: 45. Risk: High.

Track Record: Monegro had the lanky build of a basketball player as an amateur when the Red Sox signed him for $35,000 shortly before the 2020 coronavirus shutdown. In pro ball, he has gained strength, power and shown the ability to develop pitches to attack different parts of the zone. After a poor Florida Complex League season in 2022, when he posted a 7.36 ERA and 12% walk rate, he made a major jump in stuff and command in 2023 and sprinted from the FCL to High-A Greenville. 

Scouting Report: In 2023, Monegro attacked the strike zone with three pitches that project as average or better. His four-seamer has solid velocity, averaging just under 95 mph, and plays well at the top of the zone. His 12-to-6 curveball got plenty of swings-and-misses against Class A hitters, and his 88-90 mph cutter improved his ability to compete in the strike zone and keep hitters off his fastball. Monegro also has a two-seamer and splitter, though the latter is a work in progress. In order to stick as a starter, he’ll likely need to either sharpen one of his pitches into a plus offering or develop the splitter into a solid offering.

The Future: After racing across three levels in 2023, Monegro should open 2024 in High-A Greenville and could reach the upper levels by the end of the year. He has a chance to be a back-of-the-rotation starter or middle-innings reliever.

Scouting Grades
Fastball: 50. Curveball: 50. Cutter: 50. Splitter: 35. Control: 50.

Franklin Arias, SS

Preseason rank: 23
BA Grade: 50. Risk: Extreme.

Track Record: The Red Sox relied heavily on their area scouts in Venezuela amid pandemic-driven restrictions on travel early in the scouting process. The team was drawn to Arias’ natural defensive actions, bat-to-ball skills and clearly projectable frame given that he weighed 145 pounds at the start of the scouting process. After Arias signed for $525,000 in 2023, he stood out for his advanced defense in the Dominican Summer League while making enough contact to rank 10th in average (.350) and draw more walks than strikeouts. 

Scouting Report: Arias is raw offensively, but there’s room to add strength to his frame and add some power to a high-contact, line-drive approach that points to an above-average or better hit tool. Even if Arias’ power doesn’t develop, his smooth defensive actions with good range in both directions, impressive body control and strong arm give him a chance at having big league value. Heís an average runner with a chance to improve as he develops more burst. 

The Future: Though years from the big leagues, Arias stands out for his multi-dimensional potential and chance to emerge as an everyday big league shortstop.

Scouting Grades
Hitting: 55. Power: 45. Run: 50. Fielding: 50. Arm: 55.

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