Hey everyone – I’m Kyle Boddy from Driveline Mechanics. I contacted Jon a few weeks ago about writing a piece for Bleeding Blue and Teal regarding some Seattle Mariners prospects, and we settled on Joshua Fields. After I scrounged up some video from his days in college, I let Jon know that I’d be ready to break down the film and produce an article.

That was two weeks ago. Readers of my blog know that I’m not the most punctual of writers, but that’s no excuse. Sorry for the delay!

Joshua Fields is currently pitching for the West Tenn Diamond Jaxx (AA), and has thrown 13 innings, recording 18 strikeouts, 11 walks, and a single home run, good for a 4.85 ERA and a 2-0 record. While his control hasn’t been great in the minors, it wasn’t all that good in college, either – he never posted less than a 5.0 bb/9 (source: Baseball Cube). However, in 2008, that 5.3 bb/9 was paired with a ridiculous 15.2 k/9 on his way to 18 saves, so there’s no question that his stuff is outstanding. Fields throws a 92-95 mph fastball, sitting comfortable at 94, and balances it with a hammer curveball at 78-80 mph that drops off the table. He throws both pitches from a high overhead slot, tilting his trunk to attain a high arm slot and to throw on a steep downwards plane.

Scouts are somewhat worried that his fastball lacks lateral movement, but most think that the high arm angle that he throws from will create plenty of deception and get a lot of grounders, ensuring that he won’t have to tinker too much to get big league hitters out.

His pitching mechanics are after the break…

What will probably jump out at you immediately is his high arm slot – he tilts his trunk and gets that high arm slot, much like Tim Lincecum (oh, what could have been):

The four phases of the delivery that I like to analyze are Tempo, Arm Action, Ball Release, and Followthrough.

Tempo: Joshua Fields is 17-18 frames from maximal leg lift to footplant. This is Excellent. Pitchers who generate momentum into footplant not only tend to throw harder, but also relieve stress on their arm in doing so. Typically, we’re looking for anything 20 frames or below (assuming 30 FPS quality video).

Arm Action: Let’s take a closer look at his arm action:

Joshua Fields starts off with a nice smooth decoupling from the glove, but starts to flex the shoulder horizontally as his elbow passes behind his acromial line – you’ll often hear this called “scapular loading.” This can stress the anterior portion of the shoulder, causing labrum tears and rotator cuff damage in the process. Many people think that it is necessary to create elite-level velocity, but it is not. Oftentimes, pitching analysts will tell you to take the elbow behind your shoulder line while standing up – you’ll feel a stretch in the back of your shoulder – and that this is the “elastic” response that causes the unloading/loading of the scapula and is necessary to create 90+ MPH fastball velocities. In actuality, the “stretch” you feel are your rotator cuff muscles being pushed past their range of motion (ROM) and actually being compressed against your shoulder blades. Ever wonder why so many people have screwed up shoulders due to poor bench press form? Now you know – taking the elbows beyond the acromial line in a ballistic or power movement is NOT a good thing.

However, taking the elbow horizontally beyond the acromial line is not necessarily terrible – it’s when pitchers return the arm to their throwing arm side that’s the problem. This causes forearm flyout. To control this, pitchers should seek to attain a vertical pitching forearm to minimize side-to-side movement of the throwing arm. As you can see, Joshua Fields does a great job of tiling his trunk and getting a vertical pitching forearm at release; we’ll talk about this more in the next section.

Joshua Fields has what Dr. Mike Marshall calls “late forearm turnover.” This is caused by the “Inverted L” in his delivery, where his pitching forearm is hanging down vertically from his upper arm. Though Fields does not start accelerating the ball towards home plate while the arm is hanging down in this position, neither does he get the ball to the “high cocked position” in time, ensuring that his forearm will lay back violently in external rotation. For two examples of the correct position when the shoulders begin to rotate and the ball begins to accelerate, here are two still photos of Greg Maddux (great) and B.J. Ryan (awful):

Joshua Fields is at some risk of UCL bruising/rupture due to late forearm turnover, but it’s not a very bad case. I’d grade his arm action as Average to slightly Above-Average.

Ball Release: Joshua Fields has an outstanding high release point and minimizes side-to-side movement:

Pitchers experience most of their elbow-related injuries due to side-to-side movement; forearm flyout occurs when the pitcher takes the arm laterally behind the body and must return it to the pitching side of the body. This will cause the elbow to “slam closed” and will cause loss of flexion in the elbow. If you know a professional pitcher who has been throwing for 10+ years, ask him to touch his pitching hand to his pitching shoulder. Try it at home yourself, right now – you have no problem doing this, right? Professional pitchers will often be unable to touch their shoulder because when the elbow slams closed, it causes lengthening of the ulna bone in their arm, which cannot be corrected by surgery. This flaw also causes bone chips in the elbow (think Chris Carpenter), fractured olecranon processes, and UCL damage.

A vertical pitching forearm and a pronated release will minimize (if not eliminate) these flaws. Pronation occurs when you turn the thumb down – its opposite is supination, where the thumb finishes up. All pitches can be thrown with a pronated release – even curveballs.

Followthrough: We can use the above image to analyze the followthrough of Joshya Fields. Though he starts with the glove in a great high position, he lets it sag a bit and has gloveside flyout as he pulls back with the glove. This can cause minor arm recoil as deceleration becomes abrupt with the posterior shoulder working too hard to slow the arm down from centripetal force.

I would recommend to Josh that he learns to pronate the release of both of his pitches – not only will this create greater movement (and possibly release velocity) on both pitches, it will help him to limit injury to his pitching arm. He already attains a vertical pitching forearm, which is highly commendable – learning to pronate the release of pitches is much easier.

Overall, Joshua Fields has a lot of great things going for him, but he does have a few of the same flaws as many traditional pitchers. Since his innings will be limited as a reliever, he should probably not experience catastrophic injuries to his pitching forearm.

Kyle Boddy is the founder of Driveline Baseball and runs Driveline Mechanics, a blog dedicated to pitching and hitting mechanics.