San Francisco Giants: Midseason Top 30 Prospects (Nos. 20-11)

15. RHP Melvin Adon

Age: 25
Current Level: Double-A
Acquired: IFA (2015)
Future-Value Grade: 40

Adon’s report read very similarly to Jose Marte’s just a couple of seasons ago. After overpowering top prospects in the Arizona Fall League (AFL) out of the bullpen last winter, the San Francisco Giants finally conceded Adon didn’t have a future in a starting rotation.

The adjustment to full-time relief work hasn’t been a seamless one.

While his 12.0 K/9 are easily a career-high, his walk rate has also climbed to an unsettling 5.4 BB/9. Despite the free passes, he’s posted a solid 2.90 ERA, 2.96 FIP and 2.89 xFIP while converting 11 of 12 save chances in 40.1 innings of work.

Adon has a true 80-grade fastball, routinely sitting from 99-100 mph and touching 102 mph. It isn’t straight either and has some run to make it even harder to square up. He’s toyed with a two-seamer, but there’s no need to move away from one of the best heaters in organized baseball.

In the AFL, Adon began locating his slider consistently for the first time and that was a big part of his success. It only projects as an above-average pitch, but it plays up alongside his elite fastball.

Adon’s control and command will determine if he stalls out in the minors or emerges as one of the best relievers in baseball. At this point, only time will tell.