Sodo Mojo’s Top 40 Seattle Mariners Prospects: 25-21

One of my favorite selections of the Jerry Dipoto era, Damon Casetta-Stubbs is a 19-year-old righty with nice potential and a solid floor. He has a sturdy build, standing a 6’4″, 225 lbs. The Vancouver Washington native split most of his season between West Virginia and Everett and battled through his first full season of pro ball.

Casetta-Stubbs sits comfortably between 88-91, but has hit 94 MPH in games, and reached 97 MPH inside work. He has two average breaking balls that both flash above-average, as well as a changeup that has flashed enough to give him a good chance at 4 pitches.

Casetta-Stubbs has solid command and is a good athlete with a nice delivery. The combination of stuff and command at the age of 19 isn’t something you see often. We are big fans of DCS on the website and are expecting big things from him in the coming years.

He will likely start the year back in West Virginia and have an opportunity to jump to the California League for Modesto by the end of 2020.

The Mariners are having a resurgence with the July 2nd signings, and Jonatan Clase is a good example. In 64 games in the DSL, Clase hit .300/.434/.444 with 31 stolen bases and a 147 wRC+. Clase’s power shows up more with doubles and triples, but at 17-years-old, there is time for some power to develop.

But even if the power never comes, Clase has some loud tools to carry him to the majors. He has elite speed, scoring 80-grade speed with plus outfield defense in center and a cannon for an arm. He’ll have a good chance to hit for average and get on base.

Clase has a fantastic strike zone discipline and pitch recognition, especially at his age. He walked nearly as much as he struck out, producing a 17.8% walk rate. He can use the whole field and has quick hands and a solid stroke.

If Clase’s tools max out, he’s a leadoff hitter who hits .300/.380/.420 with 10 home runs and 40 steals to go along with gold glove defense in center field. Still, he is just 17-years-old so the range of outcomes is vast.

You never can predict how teenagers will progress, especially when international free agents come stateside for the first time. But Clase’s toolset is far too interesting to rank him any lower. Clase could rocket into the Top 10 with a solid stateside debut, but that may have to wait until 2021.

Since arriving in the Mariners organization, Sam Delaplane has done one thing better than anybody in the organization: he strikes guys out. In his 2 full seasons in the minors, Delaplane has struck out 270 hitters in 161 innings, good for a 15.1 K/9 rate.

What’s interesting about Delaplane is that he doesn’t have overwhelming stuff. His fastball sits 91-95. He has a nice, hard sinker. His curveball is good, but not elite. He doesn’t have pinpoint command. But the results speak for themselves.

Delaplane generates so many swings-and-misses because he excels at “Arm tunneling”. All three of Delaplane’s offerings come from the exact same arm slot and are all thrown with the same arm speed. In short, he doesn’t do anything to tip his pitches, so hitters must rely on spin recognition to hit Delaplane.

It is unlikely that the strikeout rate will become something that carries into the big leagues but at every level, Delaplane has found success. The stuff doesn’t play as well at the big leagues, and Delaplane is probably going to be a middle reliever at the big league level.

But if Delaplane can continue to defy expectations, he’ll be a weapon for the Mariners going forward. He will likely start the year in Tacoma, but manager Scott Servais has voiced a lot of support for the right-handed pitcher. Delaplane has a good shot to make the club out of spring training but will make his debut at some point in 2020, pending his health.

We wrap today’s portion of the list with our second-highest ranked reliever on our list, Joey Gerber. Why does Gerber edge out Delaplane in our ranks? Gerber has better stuff than Delaplane and it isn’t all that close.

His fastball sits 94-97 mph with great life up in the zone. Gerber gets even more value from the pitch thanks to some deception in the delivery and it is a true 65-grade pitch. Gerber’s slider flashes plus, sitting 86-89 with a sharp movement. He can overthrow it on occasion, giving the pitch a cement mix spin that stays over the plate.

He needs better control and has the stuff to get away with the occasional mistake. If he can harness his stuff and throw it with average command, he has closer potential. Gerber will probably start the year in AAA Tacoma and should see the big leagues in 2020.

Gerber should excel early as a set-up man if nothing changes, but a few tweaks to the slider and better control could land him as the closer for the next winning Mariners team.

In our next installment, we will enter our Top 20 Mariners prospects. The next group has a nice balance of high-upside plays and high-floor, probable big leaguers. The Mariners would greatly benefit from one or more of these guys from reaching their ceiling, but with the Top 10 as stacked as it is, if all 40% of them reach their 80% plateau, they’ll be just fine.