After top infield prospects Marcelo Mayer and Kristian Campbell graduated from Boston’s system in 2025, Franklin Arias took hold of the being the most promising infield prospect for the Red Sox. Arias made quick work of the lower levels of pro ball before advancing to Double-A Portland at the end of last season, being the only teenager in Boston’s system to reach Double-A, and was one of just nine players 19 years old or younger across all organizations to reach Double-A in 2025. Arias’s game starts with the advanced hit tool. He struck out only 10.1% of the time across 526 plate appearances last year between Double-A, High-A Greenville, and Low-A Salem. It’s an aggressive approach that leads to lower walk rates and less optimal contact quality, but there’s some power projection in his future that might mitigate some chase risk. Defensively, Arias is going to stick up the middle, whether it be at shortstop or second base. He has good instincts and actions along with a strong enough arm to stick at short, but he might give way to a more athletic defender in the future, sliding over to second base where he could be a plus defender. Arias has average speed on the bases that hasn’t played as well as it did in the lower levels of the minors as he stole only 12 bases across 116 games in 2025 compared to 35 across 87 games in 2024.