Sodo Mojo Presents Seattle Mariners Top 30 Prospects: 15-11,

As we continue to grind through our Top 30 Mariners prospects list, we have finally reached the Top 15. Today’s list is almost exclusively made of players who have joined the organization in the past calendar year.

Of course, this is a good thing. The Mariners needed drastic additions to their farm system to set themselves up for the future. In fact, 11 of the top 15 on our list joined the organization in that time period.

As we continue our rundown, keep in mind that you can get a breakdown of our thought process by reading the primer. For a look at who we ranked 16-20, you can click here. Remember the scouting grades are on a 20-80 scale and the probability grade is based on the likelihood they reach 75% of their ceiling. Now let’s get started.

15 Damon Casetta-Stubbs

Casetta-Stubbs first crossed my radar when the Mariners drafted him in the 11th round of the 2018 draft. He pitched at Kings Way Christian School in Vancouver, Washington and was the first high school player they selected.

The Mariners then proceeded to hand the 18-year-old a $325,000 signing bonus. This bonus is typically given out to a 5th round pick, so seeing the bonus amount certainly puts Casetta-Stubbs on our radar.

Stuff-wise, Casetta-Stubbs has a fastball with good movement that sits 91-95 mph and has been clocked as high as 97 per reports. The slider appears to be his best chance at a plus off-speed pitch with its sharp break.

Casetta-Stubbs changeup and command still need work but at 18-years-old, he has plenty of time to figure both out. He is a good athlete who also earns high marks for his makeup and feels for pitching, giving him a higher floor than most high school arms.

As for his first year as a pro, Casetta-Stubbs probably stays in Peoria for extended Spring Training and may get a few innings for Everett if everything goes right. The one comp I have heard that seems to make sense is former Mariners prospect and Boston Red Sox folk hero Derek Lowe.

With a bit of patience, Casetta-Stubbs can #3 starter upside. If the third pitch never comes, he has a high ceiling of a middle reliever with his fastball/slider combination.

Scouting Grades- Fastball: 55 Slider: 50 Changeup: 40 Command: 45 Probability: 2.5/5

14. Dom Thompson-Williams, OF

Dom Thompson-Williams, or DTW, was the third piece of the James Paxton trade along with Justus Sheffield and Erik Swanson. The 6’1″, 190 lbs outfielder had a breakout season in 2018 after a swing change allowed him to tap into some unforeseen power.

The 23-year-old swatted 22 home runs in just 100 games after slugging just 6 homers in his first 2 seasons. He spent most of his time in High-A ball where he slashed .290/.356/.517, adding 16 doubles, 4 triples, and 17 steals in 24 attempts.

He got a little pull heavy in 2018. However, he has shown an ability to hit the ball hard from left to left-center field.

There are still some legitimate swing-and-miss in his swing, striking out 102 times in 363 plate appearances. He did manage to walk 33 times though. Aside from his offensive profile, DTW has all the skills required to play a solid center field.

It seems likely that Thompson-Williams will start 2019 in AA Arkansas. If he can continue his power output while cutting down on his strikeouts, he can be a legitimate, everyday centerfield prospect.

If this were to occur, DTW would quickly fly into the Top 10 of our rankings and possibly as high as the Top 8 by mid-season. Along with Braden Bishop and Jake Fraley, DTW will get a nice look in spring training since Mallex Smith is expected to miss a few weeks with an elbow injury.

There is an outside shot he makes his MLB debut this September with a good shot to be competing for a spot on the 25 man roster heading into the 2020 season.

Scouting Grades- Hit: 45 Power: 55 Run: 55 Defense: 55 Arm: 50 Probability: 3/5

12. Erik Swanson

The secondary piece of the James Paxton for Justus Sheffield trade, Erik Swanson is almost certainly going to make his MLB debut in 2019. In fact, it could very well happen in the opening series in Japan.

Swanson has a good blend of upside and minor league production, making him a natural target of Mariners GM Jerry Dipoto. Swanson absolutely dominated AA, posting a 0.42 ERA in 42 innings before being promoted to AAA where he held his own, posting a 3.86 ERA.

Overall, Swanson posted a 2.66 ERA in 121.2 innings, whiffing 139 batters while walking just 29. It took Swanson a few years to find his footing but now looks to have a high-floor big league career ahead of him.

Swanson uses a fastball with two-seam movement that hits 94 MPH as a starter. Swanson also has a slider and changeup. Neither pitch is plus, but both are usually average offerings. The changeup has good speed separation from the fastball but doesn’t have much downward movement to generate a lot of swings-and-misses.

Swanson is a bit of a crossfire pitcher, which adds deception to his delivery but can also lead to inconsistent command of his off-speed pitches.

Scouts are still split on whether or not Swanson fits better as a starter or reliever. In shorter stints, Swanson’s fastball has hit 97 MPH. The inconsistency of his off-speed pitches makes him difficult to trust getting through a lineup multiple times.

For the Mariners in 2019, there is no reason to not let Swanson start to definitively make a judgment on that. The Mariners rotation is pretty well set in stone, so Swanson might have to start the year in AAA Tacoma, but might be the first guy called up in the event of trade or injury.

Scouting Grades- Fastball: 60 Slider: 50 Changeup: 45 Command: 50 Probability: 3/5

11. Sam Carlson, RHP

Sam Carlson is such an enigma. The high school arm fell to the second round of the 2017 draft despite being a consensus top 20 talent. The Mariners wasted no time scooping him up and paying him $2 million to secure the talented, young RHP. Unfortunately, Carlson has struggled with injuries in his pro career and is likely missing all of 2019 recovering from Tommy John Surgery.

But at 6’4″, 205 lbs, Carlson has all the makings of a solid #2 type of starter in his future. He has a clean delivery and is a great athlete. The Mariners shouldn’t push Carlson to get on the mound until he is 100% ready. The upside of showing patience could pay off tenfold.

When he was healthy, Carlson showed a 96 mph fastball with some sinker like movement. The slider is a solid-average offering, with an opportunity to be above-average. The reason Carlson has the potential to be #2 is the changeup. It was a plus pitch pre-injury and could get even better with time.

Carlson has a chance to have 2 plus pitches and a solid, above-average third pitch in his arsenal. Carlson also has above-average command and should have no problem throwing quality strikes and getting through a lineup multiple times.

Of course, the big issue with Carlson is just his health. He likely won’t be on the mound against minor league bats until 2020, and will still need a year before he can get back on track. This pushes Carlson’s ETA back to at least late in 2022, with 2023 as the most likely scenario.

The entire profile is contingent on him coming back at full strength. If he does, Carlson has a “#1 prospect in the system” type of upside. But the fact that Carlson comes in at 11 despite facing a grand total of 14 batters in his pro career, while coming off a TJ Surgery, speaks to the immense upside of Sam Carlson.

Scouting Grades- Fastball: 60 Slider: 55 Changeup: 65 Command: 55 Probability: 2.5/5

Next time, we will dig into the Top 10 Mariners Prospects. Here is where we see the most exciting names, most of whom could be in Seattle before the All-Star break of 2020. Stay tuned for more.