The advent of the 10-day disabled list has opened up a number of possibilities, and teams have just started to scratch the surface. The most visible one has been the ability to dance around the limits of the active roster. Rotating players between the disabled list and the roster provides great advantages to teams, especially to the teams with enough depth to truly gain some wins from the new rules. Because of this recently gained advantage and the increased size of bullpens in general, teams should be looking to employ the technique known as “piggybacking” far more often.
What I call piggybacking is essentially banking a long-reliever or starter-turned-reliever in the bullpen to pitch in tandem with a starter in the rotation. Often this would result in the starter going five innings followed by a four-inning save. The weird (and rarely seen) four-inning save isn’t necessary to the strategy, but it is an interesting byproduct of it.
According to Play Index, there were just three instances of a four-inning save from 2009 to 2012. In every season since, there have been at least two different four inning saves. This year there have been three, and we’re not halfway through June. One of those was Mike Montgomery entering in relief during an Eddie Butler start. This has been a conscious decision by the Cubs, it seems; even when four inning saves aren’t necessarily in play, Montgomery has been present in Butler starts quite often. Butler has had six starts this season, and Montgomery has entered in relief in three of them.
The other two instances of a four inning save this season have been from Dodgers pitchers. One was from Kenta Maeda while the other belonged to Hyun-Jin Ryu, both starters who have been rotated through the bullpen as a way of relieving pressure on the Dodgers’ crowded rotation. Interestingly enough, Maeda’s save came during a Ryu start, while Ryu’s came in a Maeda start. This sort of piggybacking and pairing could be something that even more teams explore as the practice becomes more developed. However, thus far, the Cubs and Dodgers seem to have the best opportunity to do so.
While the Dodgers could probably use the same strategy with any number of starters, given their roster construction strategy, the Ryu-Maeda combo appears to be the logical choice. Neither pitcher has seen a large amount of success as a starter because of their inability to go deep into games. When placed in shorter appearances, however, their stuff plays up and they see much more success.
In Maeda’s last two relief appearances (yes, very small sample size) he’s thrown 4 innings in each. He’s struck out 13 of the 33 batters he has faced. Ryu has had similar success; in his four innings pitched of relief, he has yet to allow a run. The sample size has been minuscule, but it’s certainly something for the Dodgers to continue to explore. Especially with the bullpen frequently taxed by short Rich Hill and Brandon McCarthy starts, it would provide needed rest by using just two pitchers in one game per turn of the rotation. The Cubs could see the exact same benefit with Butler and Montgomery.
The downside to such a strategy is perhaps not as easy to uncover. It’s a good and fine approach to a game when both pitchers perform well. So far that has been the case for both the Dodgers and Cubs in just a few games of trying such a thing. But a problem arises when the starter fails to get through even two or three innings with a lead, or if the reliever struggles out of the gate.
It’s not simply enough to designate two pitchers for a single day without any backup plan. In that sense, it may not provide the same rest for the bullpen as in the ideal scenario. In fact, there’s a chance that it could end in a catastrophic “bullpen game,” where neither primary pitcher can step up, and six or seven relievers need to enter the game, with cascading effects for at least a week or so.
The piggybacking strategy thus isn’t one that should be relied on heavily, because of the potential negative effects it can have. However, teams should be looking to find creative ways to use their arms and the 10-day DL, and piggybacking is an obvious one. The Dodgers and Cubs have unique levels of depth, the former in particular. That allows for more opportunities to experiment. However, it’s something that many teams could do well to try out. If the outcomes stay mostly positive, it allows for a subpar starter to remain in the rotation without burning the bullpen. In this day and age of baseball, that’s extremely valuable to teams looking to compete down the stretch.