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The Saber's Edge: Assessing Skills Growth, and Decline

Jeff Zimmerman

Zimmerman writes analytics-focused baseball and football articles for RotoWire. He also handles scouting and reporting for and contributes to, and Jeff is also a two time FSWA award winner, including the 2016 Football Writer of the Year award.

Predicting hitter breakouts is about close to impossible, but a fantasy owner can ride one to a championship if he guesses correctly. The key early season focus is to find these diamonds before someone else does. Also, the owner needs to make sure the early season changes are real and the hitter won't end up being cubic zirconium.

Let's examine hitters who have made significant changes to their games. The classic example of this case is when Jose Bautista burst onto the scene. The big change with him was going from a spray hitter to a pull hitter. Besides players making improvements, I will also look at some hitters who are changing for the worse.

Determining if a player has changed his game for the better is tough because of all the different stats available. The OPS leaderboard contains the names of some familiar players (Bryce Harper and Yoenis Cespedes) and some who aren't (Dexter Fowler and Daniel Murphy). In almost every case, the "breakout" has an inflated BABIP higher than .400 (Fowler and Murphy). Since 1980, only two players, Jose Hernandez (2002) and Manny Ramirez (2000), have ever posted a BABIP higher than .400. We'll look at was some stats that stabilize quickly and show if the player has changed.

The stats I decided to examine were strikeout rate (K%), walk rate (BB%), isolated power (ISO), pull rate (Pull%) and ground-ball rate (GB%). Now, here is where the match gets a little funky, so if you want, skip ahead to the next paragraph feel free. First, I found the league-wide value for one standard deviation for each of the five stats. I created one value for the total change in a player. Finally, I determined if the stat moved in the good (or bad) direction. The direction for K%, BB%, and ISO are straightforward, but Pull% and GB% not so much. For my final good value, I assumed more groundballs were bad and pulling the ball is a good thing. Now, a person can disagree and download the data to manipulate as they desire.

With the data description done, here are the 2016 players ranked by how they have changed for the better compared to the second half of last season. Click the column headers to sort.

Sean Rodriguez-2.8-19.1-0.1-
Nick Hundley2.718.23.926.4-0.2-
Yasmany Tomas-1.9-
Yasmani Grandal3.623.90.31.7-3.7-
Colby Rasmus0.
Scooter Gennett-1.0-6.71.611.
Eugenio Suarez-0.4-2.71.812.3-2.1-
Gregory Polanco0.
Bryce Harper-2.3-
Nolan Arenado0.
Jake Lamb0.
Paul Goldschmidt1.
Anthony Rizzo-0.1-
J.J. Hardy-1.5-
Carlos Ruiz-2.5-
Marcus Semien0.74.72.416.0-0.4-
Brett Gardner1.812.01.06.8-1.3-
Kevin Kiermaier-0.8-5.71.510.10.0-
Wilson Ramos0.00.01.711.3-2.4-11.8-0.7-
Ryan Braun-0.5-
Jean Segura-0.5-
Joe Mauer-1.6-10.9-0.7-4.5-1.9-
Kike Hernandez-1.8-
Robinson Cano-0.9-
Billy Hamilton1.
Victor Martinez-0.6-
Kris Bryant0.
Derek Dietrich2.114.11.510.3-0.9-4.2-0.6-
Brandon Belt-0.8-5.7-0.5-3.6-2.4-
Corey Dickerson0.
Steven Souza0.
Melvin Upton Jr.
Mike Moustakas0.
Brock Holt-1.2-
Stephen Piscotty0.53.01.510.
Francisco Cervelli0.
Christian Yelich0.
Nelson Cruz-1.3-8.51.610.9-2.2-
Jonathan Schoop0.
Todd Frazier-0.9-
Austin Jackson-0.8-5.31.711.8-2.6-12.7-0.3-1.2-1.1-.0712.86.6
Angel Pagan0.
Brandon Barnes0.
Charlie Blackmon1.
Alex Avila2.415.92.718.6-1.3-6.3-0.9-2.9-0.7-.0412.57.9
Daniel Murphy-2.1-
Gregor Blanco2.717.
Jose Altuve-0.8-5.5-0.4-
Melky Cabrera0.
Nick Ahmed-0.1-
Ryan Hanigan-4.6-31.1-2.5-17.3-1.9-9.53.611.9-0.7-.0422.313.3
Jedd Gyorko-1.5-10.2-0.6-3.9-0.5-
Brandon Crawford-1.5-
Brandon Phillips-1.0-
Yan Gomes1.
Ben Paulsen0.
Chris Iannetta1.
Dexter Fowler-0.7-4.8-0.3-2.1-0.1-
Starlin Castro-0.5-
Salvador Perez-2.6-
Tucker Barnhart-1.4-
Michael Conforto0.00.1-0.1-0.4-0.2-
Odubel Herrera-1.6-10.9-3.0-20.1-0.1-0.34.414.80.4.0251.99.4
Josh Harrison0.
Xander Bogaerts-0.3-
Brandon Moss-0.9-6.2-0.9-
Martin Prado-0.3-
Buster Posey2.415.91.611.
Chris Carter1.
Hunter Pence1.
Randal Grichuk-0.6-4.3-0.5-3.2-2.1-
DJ LeMahieu-0.9-
Freddy Galvis0.
Blake Swihart-0.7-5.0-1.3-8.9-2.0-
Andres Blanco-0.5-
Jerry Sands2.718.14.631.34.522.
Matt Carpenter0.74.9-0.1-0.6-1.0-
Jarrod Dyson-0.4-2.5-2.1-14.0-3.8-18.70.0-0.1-0.6-.0361.26.8
Alcides Escobar0.
Alexi Amarista-4.0-26.5-0.5-
Addison Russell0.64.2-1.8-12.0-1.7-
Danny Espinosa-2.2-14.7-1.2-8.1-1.8-
Yasiel Puig-0.7-
Rajai Davis1.
Yadier Molina-0.4-
Tyler Saladino-0.3-
Ichiro Suzuki-0.3-1.8-1.9-13.0-2.3-
Jordy Mercer-0.6-4.0-0.9-6.2-1.2-
Ivan De Jesus-0.7-4.7-1.6-10.6-0.4-
Mark Teixeira2.919.11.49.4-0.5-
Andrew McCutchen-2.0-
Aaron Hicks1.38.61.812.4-1.3-
David Freese1.610.
Brad Miller-0.7-
Nolan Reimold-3.0-20.4-1.4-
Brian Dozier-1.8-12.3-1.6-10.9-1.6-
Manny Machado-1.5-9.9-0.1-
Johnny Giavotella1.912.61.610.8-0.5-2.2-0.8-2.6-0.7-.0410.65.4
Adrian Beltre0.
Stephen Vogt0.
Mike Trout0.
George Springer-0.2-
Yunel Escobar1.610.8-0.1-0.4-0.5-2.6-0.4-
Pedro Alvarez0.00.2-0.1-0.7-2.4-
Josh Reddick-0.3-
Jacoby Ellsbury0.00.2-0.4-2.4-0.7-3.6-0.3-
Ryan Howard-2.5-
Kurt Suzuki-1.3-
Nick Markakis-1.4-9.2-0.3-
Adeiny Hechavarria-0.7-4.6-0.6-
Joc Pederson-0.8-5.4-0.5-
Adam Jones1.
Andrelton Simmons-0.6-
Seth Smith1.912.8-1.7-11.8-0.6-
Avisail Garcia-0.2-
Anthony Rendon-1.6-10.4-0.5-3.5-2.0-9.6-0.5-1.7-0.9-.0570.05.4
Trevor Plouffe-1.0-6.6-0.8-5.4-1.1-5.2-0.9-
Starling Marte-1.6-
Ian Desmond-0.4-2.7-1.8-12.5-1.4-
Billy Burns-0.3-2.3-1.4-9.5-1.8-9.0-0.3-1.1-0.2-.011-0.14.1
Yoenis Cespedes-2.6-
Neil Walker-2.4-
Jay Bruce-1.1-7.3-1.3-8.5-0.5-
Derek Norris1.
C.J. Cron0.42.6-0.9-6.3-1.0-
Jimmy Rollins1.711.5-0.6-4.0-0.9-4.6-0.6-
John Jaso0.43.0-0.8-5.5-2.3-11.2-0.9-3.1-0.8-.048-0.25.2
Marlon Byrd-3.4-23.1-2.1-
Jorge Soler-1.1-7.6-1.0-6.6-0.6-
Kole Calhoun0.10.4-1.3-8.9-1.6-
Anthony Gose0.74.71.913.21.04.9-0.5-1.8-1.0-.061-0.55.1
Hank Conger0.10.54.530.70.84.0-0.5-1.8-3.7-.235-0.69.7
Lorenzo Cain0.85.51.510.32.411.81.65.5-1.3-.084-0.67.7
Eric Hosmer2.
Jose Iglesias-0.5-3.3-0.7-
Kelly Johnson0.74.5-0.6-4.1-1.1-
Jayson Werth-1.0-6.6-0.5-
Asdrubal Cabrera0.
Matt Kemp-0.3-2.1-0.4-2.7-1.1-5.5-1.6-
Shin-Soo Choo-0.8-5.61.510.3-0.1-
Chris Owings1.27.8-0.3-1.8-0.6-3.2-0.9-2.9-0.3-.022-0.83.3
Francisco Lindor-0.4-
Matt Duffy-1.4-9.6-0.5-
J.D. Martinez0.21.4-1.3-8.5-2.1-10.3-0.1-0.4-1.6-.100-0.95.3
Corey Seager0.
Chase Headley0.64.1-0.8-
Brandon Guyer-0.6-4.3-0.6-4.4-0.5-
Albert Pujols0.10.5-1.3-
Miguel Montero-0.2-1.1-0.7-
Kolten Wong0.
Preston Tucker1.49.10.0-
Cory Spangenberg3.
David Peralta-0.2-1.4-1.1-7.5-0.4-2.0-0.4-
Adam Eaton1.510.3-0.6-4.4-2.0-10.0-1.8-6.1-0.6-.040-1.16.7
David Ortiz0.0-0.3-0.4-
Steve Pearce0.53.4-0.9-6.0-1.6-
Justin Bour-1.0-6.4-0.4-
Travis d'Arnaud2.315.41.17.3-0.2-0.9-0.3-0.9-2.3-.143-1.36.1
Logan Forsythe-0.3-1.7-1.6-
Omar Infante0.21.5-0.3-
Jackie Bradley Jr.
Cesar Hernandez-1.7-11.1-1.5-10.5-0.4-2.0-0.3-1.10.0-.001-1.54.0
Paulo Orlando3.
Dustin Pedroia-0.6-
Matt Wieters0.
Jose Abreu0.
Juan Lagares1.49.4-3.2-21.6-1.4-
Jason Kipnis-0.4-2.7-0.7-
J.T. Realmuto2.214.50.0-0.1-0.2-0.9-0.8-2.6-1.0-.065-1.64.2
Miguel Cabrera0.85.2-0.4-
Jed Lowrie2.516.70.42.6-0.8-4.1-1.0-3.3-1.9-.120-1.76.6
Ian Kinsler-0.2-
Prince Fielder-1.4-9.30.0-
Evan Longoria-1.5-9.9-1.3-
Hanley Ramirez-1.9-12.6-1.9-
Jose Bautista-0.1-0.9-2.4-
Miguel Sano-1.3-8.9-0.6-4.2-0.2-
Delino DeShields2.416.
Kyle Seager1.510.1-1.4-
Erick Aybar2.
Carlos Gonzalez0.21.7-0.9-6.4-1.3-6.3-0.2-0.7-2.0-.128-1.94.7
Curtis Granderson0.42.7-1.6-11.2-0.4-2.0-1.1-
Aaron Hill-0.7-
Carlos Santana-0.8-5.6-2.5-16.7-1.8-9.1-2.0-
Stephen Drew0.
Jonathan Lucroy-0.7-
Carlos Perez1.49.7-0.3-2.2-0.2-0.9-0.5-1.7-1.3-.082-2.03.8
Billy Butler-1.7-11.4-0.4-2.5-0.9-4.3-1.8-6.0-0.7-.044-2.05.4
Mitch Moreland-1.2-
Elvis Andrus-0.5-3.1-1.3-
Mark Reynolds0.00.0-1.4-9.72.411.
Alex Gordon-1.1-7.3-1.8-
Marcell Ozuna-0.1-0.4-1.0-
Travis Shaw-1.2-8.0-2.3-15.6-0.2-
Tyler Flowers-0.4-2.90.0-0.32.411.91.44.8-1.2-.075-2.25.5
Mookie Betts-0.4-3.0-0.4-
Dee Gordon-1.4-
Yonder Alonso2.315.71.610.71.05.0-1.4-4.7-1.6-.098-2.47.9
Adrian Gonzalez1.610.7-2.4-
Alexei Ramirez0.
Eddie Rosario2.718.0-1.9-13.0-0.2-
Tim Beckham-4.3-28.5-0.2-
Adonis Garcia0.53.3-0.9-
Ketel Marte-1.9-
Brett Lawrie-2.1-13.9-1.4-
Caleb Joseph0.
Rougned Odor-1.0-6.7-0.9-
Brian McCann0.53.6-0.2-1.52.612.90.41.3-0.2-.010-2.63.9
Carlos Correa0.21.2-0.6-
Nick Castellanos-1.7-11.7-0.5-3.1-0.2-1.0-1.4-4.5-1.1-.070-2.74.9
David Wright-2.5-
Justin Turner-1.2-7.8-1.4-9.70.0-0.2-0.5-1.8-0.9-.059-2.94.1
Kevin Pillar0.85.4-0.2-
Luis Valbuena2.013.3-0.4-
Jason Heyward-2.2-
Didi Gregorius1.06.4-1.1-
Nori Aoki1.49.5-0.6-
Wilmer Flores-2.1-13.8-0.6-4.22.411.82.27.4-2.4-.148-3.29.6
Josh Donaldson-2.1-14.2-1.0-
Ryan Zimmerman2.214.7-0.3-1.9-1.1-5.6-0.4-1.3-3.8-.241-3.47.8
Michael Taylor0.85.5-2.0-
A.J. Ellis1.38.4-1.3-8.7-0.8-3.8-1.5-5.0-1.4-.086-3.46.2
Kendrys Morales-0.2-1.3-0.1-
Jace Peterson-1.8-12.1-0.9-
Chris Coghlan-0.7-4.8-1.3-
Ryan Goins0.64.1-0.5-3.3-0.3-1.7-2.4-8.0-1.1-.067-3.64.9
Jason Castro1.912.4-2.6-
A.J. Pierzynski0.96.3-1.0-
Jeff Francoeur3.221.4-0.8-
Howie Kendrick-0.3-1.9-0.7-
Joey Votto1.28.32.516.7-0.5-2.3-4.5-15.1-2.6-.162-4.111.2
Lucas Duda2.
Chris Davis-0.5-3.6-3.7-
Cameron Rupp0.
Carlos Beltran1.912.5-0.4-3.02.311.1-2.0-6.8-0.2-.012-4.96.8
Marwin Gonzalez-0.7-4.9-1.7-11.72.411.8-0.8-2.8-0.1-.005-5.05.7
Franklin Gutierrez3.
Trayce Thompson2.516.6-1.3-
Mike Napoli1.711.3-1.2-
Freddie Freeman-2.2-14.7-1.1-7.42.411.7-0.5-1.7-1.3-.082-5.37.5
Jose Ramirez-0.5-3.0-2.0-
Chris Colabello2.214.4-1.7-
Eduardo Escobar-1.2-7.8-1.8-
Adam Lind-0.2-
Alex Rodriguez-2.2-14.8-2.5-
Khris Davis0.96.2-1.5-
Edwin Encarnacion0.
Justin Smoak-5.0-33.5-1.8-
Justin Upton-1.1-
Logan Morrison1.510.
Evan Gattis-1.2-8.3-1.1-
Darin Ruf-1.8-12.2-2.5-17.12.311.5-0.6-2.1-2.8-.173-8.210.1
Mark Canha-1.7-11.4-3.5-23.55.728.2-2.0-
Russell Martin-0.6-4.3-0.3-1.94.723.4-1.3-4.2-3.4-.216-9.710.4
Chris Young-2.3-15.4-4.2-28.43.818.6-1.3-4.3-0.9-.058-10.212.5

Time to dive in on some of the players, but remember we are still early in the season and are dealing with a small sample of data.

Good Change

Nick Hundley

He is having a good season, besides the concussion, if a person ignores his BABIP-driven batting average. Even with the 70-point drop in batting average (.301 to .231), his on-base percentage is higher (.339 to .375) and slugging is about the same (.467 vs .462) from 2015 to 2016. The big change with him is his walk rate tripling (5.4 to 18.8 percent). He could be a nice buy low for an owner needing a catcher.

Yasmany Tomas

This is an instance of a player improving against major league pitching, which might have happened for others while they moved through the minors. Tomas is improving almost everywhere. His walks are up and strikeouts down. He is hitting for more power and putting the ball in the air more. He is even posting a .300-plus batting average with a BABIP that has dropped from last year. I am not sold he has the power to maintain a 25 percent HR/FB rate, but he looks to be a better overall player, and congrats to owners who took a chance on him.

Colby Rasmus

I am not completely surprised Rasmus is having a great season. He has always been an OK power hitter, who with a little luck could have a great season. It might seem like he is having that season now, but his success follows some significant changes. The first change is a better eye for pitches. His K/BB has gone from 3.20 to 1.25. A 24.0 K% is quite a bit better than his the 30-percent levels from the previous three seasons. The other big change has been his ability to turn and pull the ball (53 to 62 percent) for more power.

Bryce Harper

One of the league's two best hitters improves in several areas, so now he is making a statement to be the league's best hitter by himself.

Not-So-Good Changes

Joey Votto

Votto is having a horrible season, and I think he is hurt in some fashion. Pitchers just seem to be taking advantage of him. He has displayed almost no power with an ISO less than .100. Pitchers are attacking the strike zone more (43.0 Zone% in '15 to 51 percent now). Votto is being forced to swing more and no longer rely on his perfect eye. His BB% is down nine points and K% is up.

Russell Martin

Like Votto, Martin's decline is due to the combination of no power and no plate discipline. Unlike Votto, Martin has an injury (neck) to blame. Look at his May stats and see if they are closer to his historic values as he heals.

Edwin Encarnacion

Encarnacion might be a great option for his owners to trade. His batting average is up and he has some home runs (3). The new owner might think he is buying low with the chance E5 will just start heating up. Every stat points to him getting worse. His .350 BABIP is the only value over .300 he has posted since he was with the 2007 Reds. His walk rate is cut in half (12 to 6 percent) and strikeout rate is up (16 to 25 percent). His power is down with his HR and FB distance dropping from an average 289 feet last year to 269 feet this season. Nothing seems right for him.

Justin Upton

Upton is struggling with a .208 AVG and only one home run. I feel like a broken record when I point out he has a horrible eye and no power. Upton's K/BB sits at 10.7. I don't understand how he has a 40.7 K%. While his swinging-strike rate is up to a career high 15 percent, his K% should be closer to 30 percent. I know 30 percent is not good, but it is a lot better than 40 percent. Looking over his numbers in detail, it is tough to find one item that might be the cause, but he is struggling with fastballs for the first time in his career. BrooksBaseball has a feature that describes how a hitter is doing against a pitch. Here is its description of Upton:

"Against Fastballs (243 seen), he has had an aggressive approach at the plate (-0.06 c) with a disastrously high likelihood to swing and miss (30% whiff/swing). When he connects (26 tracked), he generates average power (89.4 mph average exit velocity) and sprays the ball to all fields (-4.7 average spray angle)."

To see if Upton has turned the corner, follow this graph at FanGraphs of his recent rolling K% and see if it is dropping near to 30 percent.

Well, that is it for this week with hitters who have seen some real changes to their games. Next week, I will look at pitchers. And as always, let me know if you have any question on any other hitters.