FanPost

Building a Piggyback Rotation: A Thought Experiment

Introduction

A discussion thread today explored the concept of a piggy-back rotation, and whether such a scheme would be beneficial under any circumstances. I posited that if you found enough pitchers that were really good the first time through the lineup, and intolerably bad the second time through, there must be some optimal configuration which would make pitching two "starters" per game in series a beneficial move. Using 2013 BBref stats (where all stats below were taken from), I set out to find the pitchers with the most extreme splits between first and second time through the batting order in order to figure out what the best chimeric starting pitchers would be. This thought experiment operates under the assumption that the use of tandems would keep pitch counts low enough that pitchers could regularly go on one day short rest.

This was started mostly just to satisfy my own curiosity, but I figured I’d share with the class. I wanted to see if there really was a way to make the sum of the parts much greater than the components if you mixed the right "bargain bin" pitchers. Maybe you guys can think of ways to improve the plan even more.

Methodology:

To select the players who would fill out my "piggy-back" rotation, I first filtered pitchers with at least 5 starts last year into two separate lists. The first was the 50 starting pitchers with the largest difference between ERA the first time through the batting order and overall season ERA (I know ERA isn’t always the best measure out there, but it was easiest to sort by). The second list contained the players with the 50 highest differences between ERA for the second time through the batting order and season ERA . I then cross referenced the lists to find players who met both criterion simultaneously. The next round of selection involved removing players with ERAs below 4.0 overall for the season, as it would be unlikely that these players would be used in an experimental pitching scheme such as this one. I then calculated the FIP of each pitcher for the first and second time through the order (WARNING: Some smalls sample size effects are probably in play here, but this is just a fun thought experiment so take it with its proper grain of salt).

The players on the remaining list with the 8 lowest first time through the batting order FIP values were selected to form the top 4 pitching duos. The 8 remaining pitchers were split into two groups, those with the 4 highest FIP splits and those with the 4 lowest FIP splits. The group with the highest FIP splits will generally pitch for the first time through the batting order while the member of each pair with a smaller split will pitch the second time through the order. The reasoning for this choice is that if a pitcher is needed to go longer into late innings due to an overworked bullpen, using a pitcher with less severe splits the second time through the rotation minimizes the potential damage of having batters see them a second time. The individual pairing of pitchers was selected to maximize the difference in delivery, pitch selection, and average fastball velocity of the two "starting" pitchers.

The Personnel:

The analysis mentioned above yielded these 8 pitchers as the ideal group for a piggy-back strategy to starting pitching.

Through Order

ERA

IP

HR

BB

SO

FIP

Andre Rienzo

First

1.23

22

1

10

12

4.05

2013 ERA: 4.82

Second

9.95

19

9

11

14

9.62


I know nothing about this guy, so I’ll cite someone who does…"There are two reasons Rienzo’s curveball is such a knee-buckler, and one of them isn’t good. He can’t throw it for a strike very consistently…" "At the moment, he’s not a control-guy, not quite a groundball guy (he’s closest to showing potential there) and not a guy who can rear back and naturally get swings-and-misses because his stuff is so lively." (James Fegan, Exit Inverviews: Andre Rienzo, Nov 2013, http://southsideshowdown.com/2013/11/10/exit-interviews-andre-rienzo/)

Rienzo shows the most extreme ERA split between his first time through the order and his second. His FIP values for these innings support the possibility that this is not strictly a luck based effect. While Rienzo’s K and BB rates are fairly similar for both halves of the split, his home run rate skyrockets after hitters have seen him once. This fact puts Rienzo firmly in the "pitches first" catergory, as he gets exponentially worse after hitters adjust to his delivery.

Through Order

ERA

IP

HR

BB

SO

FIP

Daisuke Matzusaka

First

3

15

1

6

18

2.91

ERA: 4.42

Second

6.75

13.1

3

8

10

6.79


Brief synopsis: We’ve seen the Human Rain Delay 2.0 enough to know what he’s capable of. He’s shown a strong spring training so far to compete for a 5th rotation spot, but his ability to maintain long stretches of success has yet to be established. While he throws 4 pitches reasonably well, he tends to walk too many batters to be truly effective. Dice struggles from a high baseline walk rate that doesn’t seem to change much paired with a declining strikeout rate in the second go-around and a slightly elevated HR rate (small sample alert!), and his low first pass and high second-pass FIP make him ideally suited for the "pitches first" group.

Through Order

ERA

IP

HR

BB

SO

FIP

Dallas Keuchel

First

3.17

48.1

3

14

43

3.00

ERA: 5.15

Second

6.29

44.1

7

17

25

5.20

"His fastball isn't very fast, being as low as 83-85 MPH at times, though at his best he works at 86-89, which is where he was in his big league debut. His main breaking ball is an adequate curve, but his out-pitch is usually his changeup, a solid offering with good action low in the strike zone." (John Sickels, SB Nation: Minor League Ball Jun 2012, http://www.minorleagueball.com/2012/6/20/3098333/prospect-of-the-day-dallas-keuchel-lhp-houston-astros-scouting-report)

It is unsurprising that Keuchel struggles the second time through the order with a well belo-average fastball. However, he is known for having very good control and inducing ground balls at a decent clip to compensate for the lack of a power pitch. Keuchel managed to maintain a FIP of just over 5 after hitter have seen him once. While less than ideal, this is actually one of the better values that came up in this group. As such Keuchel will be assigned to the "second" group of pitchers for games when he needs to face hitters for a second time.

Through Order

ERA

IP

HR

BB

SO

FIP

Jake Peavey

First

2.85

53.2

6

12

48

3.38

ERA: 4.17

Second

6.07

46

9

14

44

4.72


The Elder Statesman and most established pitcher of the group, Peavey has been a reasonably effective pitcher for most of his career. It was somewhat surprising to find him on this list, however it appears the disparity in ERA isn’t entirely supported by differences in FIP, suggesting that batted ball profiles, or just a lot of bad luck in 2013 might play into these differences. Peavey’s strikeout rate and walk rate are fairly consistent in both groups, with a higher home run rate after batters adjust to his pitching. Overall Peavy would be a clear choice for the "second" group, as his low walk rate and relatively strong strikeout rate

Through Order

ERA

IP

HR

BB

SO

FIP

Josh Lindblom

First

3.27

11

2

2

6

4.86

ERA: 5.46

Second

10.8

8.1

2

6

4

7.49

The keystone of the trade that sent Michael Young to the Phillies, thus greatly amusing us all, Lindblom projected to be a decent relief pitcher, if he can ever get control of his secondary offerings (curve and change). He throws a decent fastball and his out pitch is an above average slider. The sample sizes for Lindblom are exceptionally small here so it’s hard to say if his splits are really this bad from the data I gathered. He appeared in 8 games, starting 5, and still only managed 31 innings for the season. I guess that counts as efficiency of some sort? Still he made my arbitrary cutoff of 5 games started, so here he is! Given his extreme volatility even the first time through the rotation (ERA far outperformed FIP despite his reputation as a strikeout pitcher), he would be placed in the "first" group.

Through Order

ERA

IP

HR

BB

SO

FIP

Robbie Erlin

First

2.21

20.1

0

6

13

2.65

ERA: 4.12

Second

5.79

18.2

4

6

18

4.91


Erlin pairs a mediocre fastball with a decent changeup and curve, using finesse to get batters out. He doesn’t have a true out-pitch to speak of that I’m aware of, but his ability to command all of his pitches seems to serve him reasonably well. The first time through the order, Erlin is lights out with an ERA and FIP well south of 3.0. His walk rate tends to remain flat no matter how many times hitters see him, as expected from a control pitcher, and his K rate actually increases the second time through. However he tends to give up the long ball more frequently the second time through the lineup, diminishing his effectiveness deep into games. While the HRs are a concern, he clearly has the stuff and control to pitch deeper into games in spite of his long-ball tendencies and would be placed in the "second" pitching group.

Through Order

ERA

IP

HR

BB

SO

FIP

Todd Redmond

First

2.53

32

3

9

38

2.73

ERA 4.32

Second

7.36

25.2

7

6

25

5.74


Redmond primarily throws a fastball and slider, and has a strong platoon split which makes him ineffective against lefties. This could lead to problems later in games where coaches can pinch hit to force him to pitch to his weaker side. The first time through the order Redmond is dominant, however the second time through the lineup his HR rate doubles while his K rate is cut to 60%. While Redmond and Skaggs provide similar profiles, Redmond’s extreme platoon split( 5.06 xFIP vs L, 3.09 vs righties) makes him a safer choice early in games than later, making him the final addition to the "first" slot.

Through Order

ERA

IP

HR

BB

SO

FIP

Tyler Skaggs

First

2.35

15.1

1

3

16

2.38

ERA:5.12

Second

6.75

13.1

2

9

12

5.72

Skaggs throws a decent fastball and a 12-6 curve which is his signature pitch. The second time through the lineup, his strikeout rate drops by 25%, while his BB rate triples, and his HR rate doubles (again small sample alert!). Skaggs has a much less pronounced xFIP split between lefties and righties (xFIP vs lefties = 3.30, xFIP vs Righties = 4.14), making him a better final candidate for the "second" pitching group.

Final Tally

Group 1:
Andre Rienzo, RHP
Daisuke Matsuzaka, RHP
Todd Redmond, RHP
Josh Lindblom, RHP

Group 2:
Robbie Erlin, LHP
Dallas Keuchel, LHP
Tyler Skaggs, LHP
Jake Peavy, RHP

Conveniently the grouping I have selected also provides me with righty-lefty pairings for 3 out of the 4 groups (I didn’t actually look at handedness until after I had chosen the groups, so it was a happy surprise). This should (in theory) help keep hitters off balance and improve the chances of the second pitcher succeeding. This would probably make Righty-heavy lineups a bit more problematic since you’ll be running a left handed pitcher out there almost every day against them, but it can’t be helped.

Pairing

The "Ace": Andre Rienzo – Robbie Erlin
The wild throwing curveball action of Rienzo followed by the pinpoint control of Robbie Erlin along with a rightly-lefty pairing will have batters guessing what to swing at the whole game. These two boast some of the best first-pass FIP values of the group, and would serve as the clear #1 pitcher on this staff.

The "Deuce": Todd Redmond – Dallas Keuchel
Redmond throws a fastball-slider combo, while Keuchel depends on a much slower fastball and a plus changeup. The decrease in pitch velocity mid-game will keep hitters off balance, which works to the advantage of Keuchel, who throws his changeup low in the zone and should be able to induce a lot of weak groundball contact. This pairing again has a very respectable first-pass FIP rating, and should fill the #2 slot as well as any single pitcher might.

The "Veterans": Diasuke Matsuzaka – Jake Peavy
The All-righty team goes to the veterans Dice-K and Peavy. Dice-K is extremely effective the first time through the lineup, with 4 pitches at his disposal to keep the hitters maladjusted their first time facing him. Peavy is capable of inducing groundball contact, and shows a much milder FIP split than the other pitchers on this list. This means he can go much deeper into games and more safely pitch multiple times through the lineup. This will allow the manager to factor in a day of rest for the bullpen, as Peavy can be relied on to pitch extra innings if required.

Back of the rotation: Josh Lindblom – Tyler Skaggs
Going from the above average slider of Lindblom to the 12-6 curve favored by Skaggs, the batter will be looking on two completely different planes for breaking pitches for the first and second phase of this pitching duo. By pitching first, Lindblom can rely more heavily on his slider and fastball, insulating him from his below average other offerings. Skaggs then rounds out the rotation since he has less severe platoon splits and is therefore less susceptible to pinch hitting situations in the later innings if called upon to pitch deeper into games.

Conclusion
I started this exercise wondering "If I were a GM and I HAD to build this sort of rotation on a reasonable budget" (it’s easy to say go sign all the aces and make them do this in a magical fairy tale world) how would I do it. Above is the thought process I went through after reading the discussion to get the players most ideally suited for this sort of work.

The first thing that I realize is that this sort of rotation could be built for pretty cheap. Most of these guys are either highly flawed prospects or journeymen late in their career. The second thing I realize is that it would be crazy to actually build a team this way. If rosters were ever expanded the experiment could be feasible as you could carry enough relievers, but with this many starting pitchers on the roster, even if you can pitch each tandem every 4 days (as I’m assuming for this exercise), the bullpen is going to be heavily worked or you will be forced to pitch your "second" pitcher through the order multiple times, largely nullifying the advantage of using guys who are very good the first time through the lineup but less effective in subsequent matchups. However, if any GM out there does want to try it out, please feel free to give my template a try, and then hire me to your front office.

This FanPost was contributed by a member of the community and was not subject to any vetting or approval process.