Anatomy of a player: Marc Rzepczynsk

In a complete ripoff of THT great Josh Kalk’s old format, I’d like to take a look one of the very talented, yet basically unheard of, young pitchers in the game. As you may have guessed by the title, I’m talking about Marc Rzepczynski, a 24 year old left handed pitcher on the Blue Jays.

In nearly 270 innings pitched in the minors over the past few years, he has had a lot of success. He struck out 9.5 batters per 9, walked 3.3 per 9 and allowed just 5 home runs. His FIP was 2.82. To top that off, over 63% of his balls in play have been on the ground. Those are legitimate Brandon Webb type numbers.

Earlier this year, Rzepczynski was called up and made his major league debut the potent Tampa Bay Ray’s offense, and pitched admirably, giving up just 2 hits and 1 run over 6, while striking out 7 batters. So far this year, he has totaled 61.1 innings for the Jays and has continued to pitch well, with a 4.10 FIP (in the AL East mind you) and a GB rate of over 50%. More impressively, in my opinion, he has continued to strike out nearly as matter batters as innings pitched.

Let’s take a look at how he’s getting it done. First, his stuff, organized by vertical vs. horizontal movement:


His fastball has a lot of variance in the movement; however, it appears that he really only throws a two-seamer. You can see a rather dense cluster at about (9,3), which is classic two-seamer territory for a lefty. Only a small amount of his fastballs were straighter, and given that they were in the exact same speed range as the two-seamers, those appear to be more accidental than by design.

It’s worth mentioning that he gets a ton of horizontal movement on the fastball. The maximum amount of movement on the fastball was nearly 15 inches, and he routinely gets over 10 inches. Despite only throwing ~1000 pitches, he ranks 17th in fastballs thrown by a lefty with at least that much break. If you put it on a rate stat, he ranks second in the majors behind Ross Detwiler. He also throws a lot of sliders, nearly 40%, and the occasional changeup.

Now, let’s check out his fastball location:


Given the obscene amount of break that his fastball generally gets, we would expect it to generate a lot of groundballs. To righties, that seems to be the case, as nearly 50% of balls put in play on the fastball have been on the ground. For lefties, the percentage is slightly higher, but it’s a much smaller sample size. He’s also shown a strong dislike for missing bats with the fastball. Only 3% of his fastballs have been swung on and missed, compared to a league average rate of about 5%.

Overall, his fastball doesn’t seem like a great pitch, or at least it hasn’t been so far. He doesn’t locate it very well, throwing just 55% of them for strikes; and while his GB rate is solid, it’s not good enough to offset the anemic swinging strike rate. FanGraphs’ pitch values agrees, have his fastball worth -1 run per 100 pitches.

The good news is that his slider has more than made up for the negative value on his fastball. FanGraphs has it at +2.9 runs per 100 pitches, which means it’s been one of the most valuable pitches in the game. While the movement or velocity on it isn’t particularly stunning, he gets a lot of separation on it from the fastball and locates it very well:


You can see he gets a ridiculous amount of swings and misses on pitches outside of the strike zone. He’s shown the ability to consistently get swinging strikes on pitches down and to the third base side of the zone. His GB rate is also very good, at 46%. As I mentioned earlier, he throws the slider nearly 40% of the time, which is one of highest usage rates in the majors.

Rzepczynski is definitely one of the more interesting young pitchers in the game. Guys who can get swings and misses and GB’s at the rate he is are usually perennial all stars. The cool part is that he gets it done while throwing offspeed pitches 40% of the time and a sub 90’s fastball.

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Using Letzner line principles, that fastball will naturally have some good tailing action. With MR’s arm slinging motion, I rememeber someone compare him to Justin Masterson.

Not surprising to see his location that bad on the fastball since he looks like he just slings the ball in the strikezone. Which likely explains the 4+ walks per nine.

A good start to follow the great Josh Kalk.