Seattle Mariners Top 40 Prospects Re-Rank: 30-26

We’re inching closer and closer to the meat and potatoes of the Mariners’ farm.

But that doesn’t mean that several intriguing names will pop up along the way. As I mentioned in the last entry to this list, the Mariners’ farm system has become significantly deep, mostly due in part to Jerry Dipoto’s activity on the trade market within the last nine months, but also for how well several of their more fringy prospects have raised both their ceiling and floor.

Where the Mariners have made huge strides this season is in adding to their pitching depth throughout the system. A pitcher-heavy draft class this past June greatly helped in building that depth, and two of those pitchers will appear on this list today, as well as another from last year’s class. In total, today we’ll be bringing you five intriguing arms that will either help the Mariners in the near future or could climb the ranks of their system over the next few years.

Let’s get started.

30. Adam Macko, LHP

Macko was the seventh pitcher of an eventual 23 the Mariners selected back in early June, coming out as an 18-year-old prep arm out of Canada. Pitchability is the key for Macko, who is still really trying to figure out his stuff altogether. Right now, his repertoire is less-than-dazzling, but an uptick in velocity could help change things pretty quickly. But if he can locate efficiently, which he has in the past, that’s all that really matters.

At 6’0″, 170 lbs., there’s still a lot of room for Macko to grow physically, and that should bring more power into his game as he develops. He’s taken well to pro ball thus far, striking out 28 batters in 18.1 innings in the AZL, which earned him a promotion to Everett. But it won’t be until next season that we’ll see what the Mariners can do with him. For now, Macko’s an efficient out-getter with the potential to be a back-of-the-rotation stud.

29. Michael Limoncelli, RHP

Perhaps the most ballsy move the Mariners made in this year’s draft was selecting Michael Limoncelli in the sixth round. The exciting prep arm was expected to be a top 100 pick in the draft before tearing his UCL, which almost certainly cemented a path through the college ranks with Coastal Carolina. But on the day of his Tommy John surgery, the M’s took him and quickly shovelled over the money it would take to turn him pro.

Clearly, the Mariners have an extraordinary amount of faith in Limoncelli to return to form. Before the injury, Limoncelli was well advanced for his age, flashing mid 90s velocity of his fastball and above-average spin on his curve. To be able to rehab under the supervision of the Mariners should help him get back to full strength without much issue, so where do they go after getting him to that point?

Really, it’s about developing a third pitch in Limoncelli’s repertoire. Whether that be the changeup he used on occasion in high school or something entirely new, Limoncelli has to expand his arsenal. Still, we’re a long ways away from discussing Limoncelli’s future as a big leaguer and won’t be able to get a look at him in pro ball until this time next year at the earliest.

28. Joey Gerber, RHP

It’s not an over exaggeration to say the Mariners have a ton of legitimate Major League-caliber relievers in their farm system, so it’s hard to really identify the best of the best, but Joey Gerber has jumped out to the front of the pack. Seattle’s eighth-round pick of last year’s draft has dominated the minor league circuit in his first full-year of pro ball, now helping lead the charge of Double-A Arkansas’ world-beater of a bullpen.

When Gerber makes his MLB debut in the next year or so, he should be atop the league leaders in spin rate on a fastball that maxes out in the upper 90s. Pair that with a devastating slider that cuts hitters in half and you have a legit future high-leverage reliever waiting in the wings. We’re not very big on relief prospects in general so that’s why Gerber wound up so low on our list, but it’s hard not to be excited about what he can bring to the table rather soon.

27. Raymond Kerr, LHP

This is a great example of a fringy Mariners prospect who’s completely changed his outlook in 2019. Being a starter was simply not in the cards for Kerr, who couldn’t maintain control over the course of a multi-inning stint and failed to develop a tertiary pitch to write home about.

Since converting to the bullpen, the 24-year-old’s control issues have subsided and he’s been able to tap into triple-digit velocity on a consistent basis. There are only a handful of left-handed relievers who can hit those numbers and locate efficiently at the Major League level, and Kerr has shown an ability to do just that in Modesto. If that continues at Double-A Arkansas next year, then the sky is the limit for Kerr moving forward.

26. Brayan Perez, LHP

Perez is somewhat of a polarizing figure within the Mariners’ organization. Some around the league really like him, while others are fairly underwhelmed. Ultimately, most of the information on Perez is hearsay since he’s been tucked away in rookie ball for the majority of his young professional career. With Perez now in Everett, however, there’s a bit more to work off of, but still not a whole lot.

From the little we’ve seen and everything we’ve heard, Perez is an efficient thrower with three legitimate pitches and a changeup that isn’t far behind. The velocity of Perez’s fastball appears to be more often on the right side of 90 than not this year, while both of his breaking pitches have been effective crutches for him to rely upon. With several legitimate options at his fingertips, Perez distributes his pitches rather evenly and can change his gameplan on the fly.

Right now, Perez has been piggybacking starts in Everett with some success, posting a 2.58 FIP in 20.2 innings pitched thus far. West Virginia will most likely be his new home to start 2020, so it’ll be interesting to see how he adjusts from competition against rookies and developing international signees to more advanced hitters.