Pre-2022 Blue Jays Top Prospect Countdown – No. 5: Sem Robberse

Brennan Delaney
1 year ago
I’d argue that Sem Robberse is the best pitching prospect in the Blue Jays organization. 
Like with quite a few prospects on this list, I’ve written about Sem before. This is to say that I’m very high on the 20-year-old.


Robberse signed with the Blue Jays during the 2019 International Free Agency period. However, unlike most players signed in the International Free Agency, Robberse doesn’t come from the Caribbean or Central America.
No, in fact Sem comes from the Netherlands, a country that tends to play a lot more futbol. I noted this in my previous article about the 20-year-old, but there have only been two players that have come from the Netherlands proper that have over 1000 plate appearances or 500 innings. One is a hall of famer, the other was Derek Jeter’s replacement.
The then 17-year-old only pitched 10.1 innings in his first professional season, but my lord did he ever look good. He had a 0.87 ERA and a 2.05 FIP with a K/9 of 7.84 without issuing a walk at rookie level.
Of course with all minor leaguers, he missed the 2020 season due to a global pandemic, so coming into the 2021 season, Sem didn’t even rank on the Blue Jays Top 30 list according to Baseball America.
If you want to read more, check out Future Blue Jays’ article here, where he goes more into depth about his upbringing and mechanics. 

Sem’s 2021:

Sem started the 2021 season in Low A Dunedin where he pitched 57.2 innings. During that time, he had a 3.90 ERA and 3.63 FIP. While on the surface level, that doesn’t seem incredibly impressive, he also had a K/9 of 9.52 and BB/9 of 3.12.
For a 19-year-old pitching in his first full professional season, he did quite well. Especially when you consider that 19-years-old is -2.9 years younger than the average pitcher in Low A last season.
This warranted a call up to the Vancouver Canadians in High A. The then 19-year-old didn’t do fantastic in his 31 innings pitched, as he registered a 5.23 ERA and 5.20 FIP. His K/9 decreased to 8.42 and his BB/9 elevated to 5.23. It’s important to keep in mind that Robberse was a 19-year-old pitcher in High A, -4.2 years younger than the average pitcher.
Robberse also settled down after his first game. In that game, he pitched only 2.2 innings, giving up four earned runs (9 runs in total). After that rough game, he pitched 28.1 innings and registered a 4.45 ERA. Interestingly, his BB/9 decreased to 4.13 while his K/9 increased to 9.21, which means he showed improvement.

What the scouts say:

Robberse ranks as Baseball America’s 13th best Blue Jays prospect, 7th best prospect for MLB Pipeline best Blue Jays prospect and the 8th best prospect in the Blue Jays organization according to Fangraphs.
According to all three of Baseball America, Fangraphs and MLB Pipeline, Sem Robberse has a fluid delivery, which was self taught as he was born in the Netherlands. He only recently turned 20-years-old, meaning that he will add on more pounds (180 lb) to his 6’1 frame.
Despite that, Sem’s fastball sat at 93-95 mph at the end of the 2021 season, according to MLB Pipeline’s bio on the young righty. Sticking with MLB Pipeline’s bio on Sem, he is fantastic at receiving feedback and instantly implying it on the mound. In fact, in lieu of the 2020 season, the then 18-year-old spent time working on mound strategies.
He has the potential as well as the right mentality to continue to rise through the majors. Let’s take a look at his grades according to MLB Pipeline and Fangraphs.
Tools/PitchMLB PipelineFangraphs PV (FV)
Fastball5545 (50)
Curveball5550 (55)
Slider5045 (55)
Changeup4530 (50)
Control5030 (50)

Robberse in 2022:

It’s likely that the 20-year-old will start his season in High A with the Vancouver Canadians. Robberse already has experience in the league, but he should be looking to improve on what he did with Vancouver last season.
Baseball America notes that Robberse could be a 20-year-old in Double A, so Robberse is definitely a pitching prospect worth keeping an eye on!


No. 20: Zach Logue
No. 20 Redux: Adrian Pinto
No. 19: Vinny Capra
No. 18: Hagen Danner
No. 17: Gabriel Martinez
No. 16: Kendry Rojas
No. 15: Kyle Johnston 
No. 14: Adrian Hernandez
No. 13: Sebastian Epsino
No. 12: Ricky Tiedemann
No. 11: Adam Kloffenstein
No. 10: Yhoangel Aponte
No. 9: Manuel Beltre
No. 8: Samad Taylor
No. 7: Leo Jimenez
No. 6: Spencer Horwitz
As always, you can follow me on Twitter @Brennan_L_D. I’m around 340, but my goal is to hit 500 by the all-star game.

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