The Arizona Fall League provides minor leaguers with a stage in which they can enhance their prospect status. Despite a rough outing (3 IP, 5 H, 3 BB) yesterday, St. Louis Cardinals minor league right-handed pitcher Tyrell Jenkins has been doing just that. Though he was not named to the league's All-Star team, his performance suggests otherwise.

GS ERA IP H ER HR BB K BAA 5 1.77 20.1 19 4 1 8 14 .253

First and foremost, when looking at these numbers, the sample size of five abbreviated starts must be taken into consideration. The ERA is fantastic, especially given the amount of offense in the Fall League (five of the six teams have team ERAs above 4.20). For perspective, his 20.1 IP is fifth most in the league, and his corresponding ERA (1.77) is the lowest of any pitcher with at least 20 IP (Mark Appel: 21.0 IP, 3.43 ERA). The amount of hits (19) and walks (8) he has allowed can be worrisome, but much of this was negatively inflated by his one rough outing (yesterday). Could his strikeout percentage be a little higher? Absolutely, and this is definitely something to keep an eye on as his development progresses.

A few highlight videos via MLB Prospect Portal

Six pitch strikeout of Addison Russell (K pitch: breaking ball)

Prior to 2014, Russell was rated the number seven prospect in all of baseball. He was not much of a problem for Jenkins here.

The strikeout hammer in GIF form (via @mstreeter06)

Feel free to watch this over and over again. Pay close attention to the height of the ball roughly half-way to home plate and then again when it was caught by Cody Stanley. Nasty.

Five pitch strikeout of Dalton Pompey (K pitch: changeup)

Of note, the 21-year-old switch-hitting Pompey saw big league action (43 plate appearances) last season with the Blue Jays, so he should have at least some experience with quality changeups. This doesn't seem to be the case when looking at the last two swings of this at bat. Jenkins's ability to throw his fastballs and changeup from virtually the same vertical release point (as you will see below) provides the deception of this pitch.

Four pitch backwards K of Tony Renda (K pitch: breaking ball)

Despite losing a fastball on the first pitch, Jenkins rebounded by throwing three straight strikes and painting a hard, sharp breaking ball on the outside corner for the backwards K. An inside fastball followed by an outside breaking ball is a perfect example of the set-up pitch concept.

Limited, but still intriguing PITCHF/x data available via BrooksBaseball

When looking at the following information, please remember that Harry Pavlidis and Dan Brooks, the brains behind BrooksBaseball, have yet to apply park corrections to Arizona Fall League PITCHF/x data. Also of note, only two starts (121 pitches) by Jenkins have been tracked by the system, so sample sizes must be taken into consideration. With all that being said, the present PITCHF/x data is very promising.

Pitch Frequency Velocity (MPH) Dragless H. mov. (in.) Dragless V. mov. + gravity (in.) V. release point (ft.) Fourseam 43.80% 93.57 -9.33 -14.41 5.92 Twoseam 16.53% 93.56 -13.50 -16.72 5.91 Changeup 22.31% 84.74 -10.77 -20.82 5.94 Curveball 17.36% 82.15 2.87 -41.10 5.82

There are a handful of things that stand out from this sample size of PITCHF/x data. Jenkins has mixed his pitches extremely well, throwing non-fastballs roughly 40% of the time. Though his fastballs' average velocities are not necessarily overpowering at 93-94 MPH, Keith Law stated in this ESPN Insider article that Jenkins was throwing "93 to 96 MPH with good downhill plane" when the writer was in attendance on October 10th. It is safe to consider 96 MPH overpowering, especially if Jenkins is able to set up his fastballs with the devastating curveball and potentially plus changeup we saw in the videos embedded above.

Jenkins has significant movement (both horizontal and vertical) on each one of his pitches. This already can be seen in the videos provided above and is reinforced by Law's usage of "downward plane" in his brief scouting report. The drop-off in velocity on his changeup from his fastball fits the desired range perfectly. Finally, as Jenkins has stressed and as many scouts have stressed as well, the righty needs to focus on producing a "repeatable delivery." The vertical release point data shows that he is well on his way to being successful with this. His fastball release points are virtually identical, and his changeup is not all that far off, either.

2015 outlook

Barring any physical setbacks, specifically related to his surgically-repaired right shoulder, Jenkins will likely start 2015 with Double-A Springfield. I don't expect him to be there all that long, and a 2015 arrival to the bullpen of Busch Stadium is a very real possibility. Long-term, however, he will provide much more value as a starting pitcher, especially if he is able to hone in on the command of his offspeed pitches.