Scouting Report

Scouting grades: Fastball: 50 | Slider: 45 | Changeup: 55 | Control: 55 | Overall: 40

The Mariners took Beilenson as a money-saving senior sign in the fifth round of the 2024 Draft, with his $25,000 under-slot bonus helping pay to sign Ryan Sloan. But Beilenson had success in college, especially once he moved to Duke after three years at Brown, saving 12 games for the Blue Devils while getting a pair of graduate degrees. While he was old for the High-A level where he began his first full season of pro ball, he pitched well enough to earn a promotion to Double-A after 20 appearances, putting him on the prospect map.

Now 26, Beilenson is more a sum-of-his-parts kind of pitcher than a reliever who is going to blow hitters away. He has a foundation of three pitches but manipulates them into different shapes to give him a repertoire of as many as five. He’ll throw both a four- and a two-seam fastball, averaging around 93 mph. His best pitch is his kick-change that has splitter-like action to it. He’ll throw both a sweeper and a shorter, harder slider around 81 mph with cutter-like action.

Beilenson can throw a ton of strikes with all his offerings, but it’s control over command, and he got hit more once he got to Double-A. If he can find a bit more consistency from one outing to the next, he could be knocking on the door to a big league bullpen job. 

Scouting grades: Fastball: 50 | Slider: 45 | Changeup: 55 | Control: 55 | Overall: 40

At first glance, Beilenson looked like the kind of senior sign taken in the top 10 rounds of the 2024 Draft to help pay for an over-slot signing; in this case, right-hander Ryan Sloan. A late bloomer who spent three years at Brown, then two at Duke, Beilenson got some attention for saving 12 games as a graduate student closer for the Blue Devils in 2024. The Mariners took him in Round 5 and signed him for just $25,000, more than $400,000 under slot. In his first full season of pro ball, he’s looking like more than a money-saver, pitching his way from the bullpen with High-A Everett to Double-A Arkansas.

Beilenson has found success as a professional reliever with three pitches and a feel for all of them. His fastball averages around 93 mph and tops out at 95, though he misses a fair amount of bats with it. He has a short, hard slider thrown at around 81 mph that can be effective, but his best pitch is his kick-changeup, thrown with almost split-like action to it.

Pitching only from the stretch, Beilenson has a compact arm action with some deception, making it hard for hitters to square up any of his offerings. And even though there’s some effort in his delivery, he’s proven to be a strike-throwing machine, one who could defy the odds and carve out a middle-relief role in the big leagues.

Transactions

Team	Date	Transaction
	03/05/2026	RHP Charlie Beilenson assigned to Seattle Mariners Prospects.
	02/05/2026	Israel activated RHP Charlie Beilenson.
	01/30/2026	Seattle Mariners invited non-roster RHP Charlie Beilenson to spring training.
	06/24/2025	RHP Charlie Beilenson assigned to Arkansas Travelers from Everett AquaSox.
	04/01/2025	RHP Charlie Beilenson assigned to Everett AquaSox from Modesto Nuts.
	03/06/2025	activated RHP Charlie Beilenson.
	02/22/2025	RHP Charlie Beilenson assigned to Seattle Mariners.
	08/27/2024	Modesto Nuts activated RHP Charlie Beilenson.
	08/27/2024	RHP Charlie Beilenson assigned to Modesto Nuts.
	07/23/2024	Seattle Mariners signed RHP Charlie Beilenson.
	03/07/2024	RHP Charlie Beilenson assigned to Duke Blue Devils.
	05/24/2023	College Workout activated RHP Charlie Beilenson.
	05/24/2023	College Workout activated RHP Charlie Beilenson.
	04/02/2023	RHP Charlie Beilenson assigned to Duke Blue Devils.