Tom Stuifbergen is the only one that has experience in organized baseball, and has been in the Minnesota Twins' organization since 2007. Stuifbergen is a 24 year old right-hander listed at 255 pounds. He has just one appearance in AA, so he is a little behind as a prospect, excelling when he repeated A+. He has been a low walk, mediocre strikeout, low home run pitcher in his minor league career. Here is what his stuff looks like, via a spin and speed chart:
He has to get the change and slider down a little more, and his fastball was extreme arm side, and probably was too high in the zone. He needs to get on top of the ball better than he did in the outing.
David Bergman is a 31 year old pitcher that has 94 career starts in the Dutch Major Leagues. We need to get some context statistically for the league (I don't have park factors for the league). We don't really know the talent level of the league, and just using the data from baseball reference, it seems to be a league that is incredibly unbalanced. One team went 34-7, and another team went 5-37 in 2012. Only 3 of the 8 teams were under .600, but they all won less than 20% of their games. So far in 2013, one team is 2-25, another is 23-3. As a league, over the past three seasons the average ERA has been 4.11, 5.05 Runs Per Game, and 3.53 FIP (homers are very rare, lot of walks, not many strikeouts comparitively). So we will use those numbers for comparing to league average. Bergman has numbers in the league since 2007, and has a career 42 ERA -, 47 R/G -, and 68 FIP -. In 2013, he has a 28 ERA -, .42 R/G-, and 50 FIP -. In other words, he has been really dominant in the league and is still on top of his game. He has a mediocre fastball, getting it up to just over 90 a couple of times, but mainly sitting at 85 MPH:
Kevin Heijstek is a 25 year old with data since 2007 in the Dutch Major Leagues. The 6-4 right-hander has a career 47 ERA -, 48 R/G -, and 76 FIP - in his career. In 2013, he has a 14 ERA - (not a typo), 19 ERA -, and 53 FIP -. His fastball didn't get up to the Bergman's, or even 90 MPH, but his average fastball might be a little bit better.
He also seems to have curve, change, and slider. His release point is also further out than Bergman's, and not any higher:
The MLBAM tags says he throws only three different pitches:
In his outing, he did a better job of getting the fastball down than Bergman, but the change stayed up, and he located the curve like a slider.
Berry Van Driel is a 28 year old 6-6 right-hander with data since 2007 in the Dutch Major Leagues. He has worked mainly as a reliever with a career 59 ERA -, 62 R/G -, and 93 FIP -. So far in 2013, he has a 14 ERA -, 23 R/G -, and 53 FIP -. His fastball seems to be much better than Bergman or Heijstek:
His release point is very similar to Heijstek's, but was really inconsistent in his outing:
This seems to explain why his average strike zone looks pretty bad:
Johnny Balentina appears to actually be a position player in the Netherlands, at least that is the only Johnny Balentina I can find. He's a left-handed sidearmer:
He's also an extreme soft-tosser:
Really just two pitches, nothing over 83 MPH, fastball/curveball. The MLBAM tags called all his fastballs "changeups", but since he didn't throw anything harder, I just called them fastballs:
The "slider" designated by the MLBAM tags is probably a curveball.
Here are the average locations of all pitches thrown for each of the 5 pitchers:
You can see that Berry Van Driel had his serious problems, and Stuifbergen was a little too high as well. Balentina was pretty standard for a lefty, while Hiejstek pitched low in the zone and glove side, with Bergman having a very standard right-handed pitcher location.