Three sleeper prospects to watch for in spring training 

The Mariner farm system is rising thanks to high-profile prospects landing on various Top 100 lists this offseason. ESPN Insider, Kiley McDaniel has the system making a massive jump from 29th to 17th in baseball due to a strong quartet of Colt Emerson, Cole Young, Harry Ford, and Lazaro Montes. With spring training a mere 17 days away, these prospects and more will ascend upon the Peoria Sports Complex backfields, bringing youthfulness and loud tools. However, the prospects listed above are just some to watch this spring. 

Brody Hopkins, a Mariner's 2023 draft class member, technically didn't start his professional career last season. Hopkins worked out and joined the slew of new Mariners in the Arizona Complex League, but he didn't get any game time on the mound or in the outfield. The 22-year-old two-way player has a mid-90s heater and a slider that grades well (55), but it's the command that might keep the former Winthrop University star down. The hope is Hopkins's elite athleticism will allow him to repeat his delivery and hone in on the command and control issues that plagued him in college. 

Another player to watch is the Mariners' 14th-ranked prospect, Cole Phillips. The 20-year-old flame thrower came over to Seattle in the oft-panned Jarred Kelenic trade. Phillips has the best fastball in the system, often ratcheting it up to triple digits (70-grade), and a sharp-breaking, above-average slider, which might position him for a closer role in the future. The former Brave is coming off 2022 Tommy John surgery, making his action in Peoria the first of his professional career. The Mariners pitching development staff will probably continue to take things slow with Phillips as he finds his footing. 

Lastly, Felnin Celesten was the Mariners' top international signing period catch last season, but fans only got a little of a look at the 18-year-old shortstop. A grade 3 hamstring strain derailed his season and kept his first stateside foray on the backfields of Arizona. Celesten has one of the higher ceilings in the Mariner's Top 30. He offers above-average tools, with the hit (55) and the arm (60) shining right now. Comparisons range from Andrelton Simmons to Francisco Lindor, with the latter being the hope. Look for the switch-hitting shortstop to get plenty of run this spring as the Mariners look to catch his development up to his peers in the class.

Those are three reasons to pay close attention to the late-inning replacements and split squad box scores this spring. Each player might get a handful of innings or at-bats with the big league club throughout spring training. However, the backfields should be electric thanks to some recognizable names and these sleepers.