The Yankees, Shohei Ohtani, and a Six-Man Rotation

Over the next few days, Shohei Ohtani, one of the most coveted baseball players in the sport’s history, will be reviewing a questionnaire he proffered to the 30 major league teams for his services. Not long after, and certainly before the new year, the 23 year-old will decide on a new home partially based on his survey. The fortunate team that Ohtani selects will be getting a 23 year-old who has already transcended the game in his home country, Japan. With his ability to pitch and hit at a high level, Ohtani will have an opportunity to do the same in the majors. Though the focal point of his potential impact is how he could open the door for more two-way players in the future, his versatility isn’t the only way he could change the sport as we know it. In recent years, teams have toyed with six-man rotations, something that is customary in Japan, but have never fully committed to it over an extended period. Now, with Ohtani coming over to North America, perhaps teams will take a harder look at the potential benefits of adding one more pitcher to its starting staff. There’s already speculation that the Yankees would transition to a six-man rotation if Ohtani joins the organization.

There are reasons that teams have avoided regularly fielding a staff of six starters to this point. For one, it’s challenging to assemble that many quality starters at the highest level. It’s also rather difficult to keep that many healthy at a time. The Yankees certainly have an array of qualified starters in Masahiro Tanaka, Luis Severino, Sonny Gray, and Jordan Montgomery, so adding Ohtani to the mix would make for a splendid rotation. Lest we forget CC Sabathia, who wants to rejoin the Yankees, and would give the team six bonafide starters. Clearly, depth isn’t an issue for the Yankees, though health is a much more complicated consideration. Ideally, the Yankees could trot out a six-deep rotation, but injuries are inevitable, and whether or not it remains worthwhile to maintain a sextet of starters over 162 games is up for debate. This isn’t the first time anyone has pondered the merits and drawbacks of fielding six starters, and it won’t be the last. Here’s what the Yankees are probably considering with regard to a six-man rotation with Ohtani in the cards.

It could protect the team’s valuable young pitchers

Transitioning from five to six regular starters could help prevent injury. FiveThirtyEight’s Rob Arthur studied injury data from Baseball Prospectus spanning from 2006-2014 to analyze the relationship between rest between starts and injuries:

“I found that there is a strong link between rest and injury rates. Looking at starts on three days of rest, 1.7 percent of pitchers suffered a reported injury within the next two weeks. At four days of rest, the typical amount in the modern age, that number drops precipitously to 1.0 percent. (Maybe that helps explain why the five-man rotation came to be.) Then the injury risk falls even further: at five days of rest — which would be standard for a six-man rotation — just 0.8 percent of pitchers are injured in the next 14 days, for a 20 percent decrease compared with four days of rest. That is a potentially meaningful drop in injury risk.”

The health advantage is greater when moving from four to five starters, but the improvement is still stark when adding a sixth hurler. An extra day of rest allows for additional recovery between starts, and further, because a six-man rotation would lead to fewer starts and innings in a season, perhaps there would be less wear and tear over a 162 game schedule. And what do you know, Baseball Prospectus’s Russell Carleton has found that a prior year’s innings pitched can be a decent predictor of future elbow and shoulder injuries. Eno Sarris has noted that in Japan, Nippon Professional Baseball pitchers are on a six-man schedule and have a significantly fewer Tommy John surgeries compared Major Leaguers. There certainly seems to be something to this six-man rotation thing, at least with regard to health benefits. Now, it should be noted that single-game pitch counts and prior injuries are the best predictors of future pitcher injuries, but clearly, rest and innings matter. And, even with a precautionary five days of rest, pitchers still get hurt. It’s not a magical elixir that would prevent the Yankees from needing to dip into the organization’s minor league depth for a handful of spot starts.

Even though it’s not foolproof, an extra day of rest would protect the young arms of Severino, Montgomery, and hopefully Ohtani. Further, over the course of a season, their workloads could be reduced by 30 to 40 innings (maybe slightly less depending on a playoff run), which may have long-term benefits. It might be helpful for prospects like Justus Sheffield and others when they get their feet wet in the majors, too. Of course, this would stand to benefit Tanaka and Gray as well, even though they are older and aren’t under team control as long as Severino and Montgomery (and again, hopefully Ohtani). Last but not least, Ohtani is coming off a season derailed by thigh and ankle woes, so thrusting him into the workload of a typical five-man rotation might not be a good idea anyway.

How would each pitcher’s between-start routine be affected?

Considering that Ohtani is already accustomed to an every sixth-day schedule, his transition to the majors would be easier without having to adjust to a shorter reprieve between outings. That isn’t to say that he couldn’t handle starting every fifth day, as there have been plenty of pitchers that have arrived from Japan that have succeeded in five-man rotations. From Tanaka to Yu Darvish, Hiroki Kuroda, and Hisashi Iwakuma, there are plenty of examples.

As for the rest of the rotation, adjusting to an extended break might be more difficult. Well, perhaps not for Tanaka, who like Ohtani has been through the procedure before. However, it’s not clear how comfortable Severino, Gray, or Montgomery would feel about it. Interestingly, Sabathia would be open to the idea. There’s no real way to know how players feel about the adjustment without asking them, but others have done some research into the performance effects stemming from more rest, which leads me to…

Would performance improve because of extra time off?

In a study of starters from 2010 through 2014, Carleton also looked at how pitching on an additional day of rest affects performance:

“Did the extra rest make a difference? No. I looked at strikeouts and walks and home runs and singles and a few other outcomes. Pitchers pitching with extra rest don’€t actually show any extra ability. They don’€t suffer for it either. They just kinda pitch like we would normally expect.”

Apparently, there’s not much of a difference when it comes to a player’s talent with more rest. On one hand, one might hypothesize that a pitcher’s stuff might be sharper and velocity higher with a longer breather leading up to an upcoming outing. That sounds reasonable, although a pitcher’s talent is generally inherent, and if it was easily improved with an extra day of rest, teams wouldn’t be sitting on their hands with rotations as is anymore. Then again, keep in mind that this study is from 2010 through 2014 when no teams regularly employed six starters. Rather, these instances are usually from when a random off day resulted in an extra day of rest for any given starter. Perhaps pitchers would be more effective once getting into the routine of extra rest, though that remains unproven and again, merely a hypothesis. Carleton’s study is certainly the benchmark at this point, and it’s at least comforting that an added day between starts doesn’t hurt performance.

As Carleton later mentions in the same piece, there’s a dilution effect to consider as well. Because each pitcher loses roughly five starts in a six-man rotation compared to a five-man, the better pitchers cede some innings to inferior pitchers over the course of a season. This is certainly one of the negative impacts of using a six-man rotation, particularly if the back-end of the staff is weak. Carleton’s piece paints a broad brush indicating that the average staff (in 2014) might lose 15 to 20 percent of its value by regularly employing a sixth starter, which could be up to two wins. From the Yankees’ perspective, the potential loss of value likely isn’t as significant, considering that Montgomery and Sabathia could be the best fifth and sixth starters in the league.

Roster construction

A tricky aspect of fielding six starters would be the ramifications to the rest of the roster’s composition. We’re accustomed to a squad of 13 position players and 12 pitchers, with seven of those 12 pitchers being relievers. With six starters, management must decide to either eschew one bench positional player or one reliever.

In the American League, going with three bench players instead of four isn’t such a big deal. After all, there aren’t many instances when utilizing a pinch hitter is appropriate. Going with three bench players would mean a backup catcher, a backup infielder, and a backup outfielder. Over a long season, it could result in some difficulty providing proper rest to all players, but it shouldn’t hurt in-game strategy too much.

On the contrary, going with only 6 relievers would be problematic. Given what we now know about the dangers of high pitch counts and the times through the order penalty, bullpens are often working 3 or more innings per game. With one fewer reliever, additional strain would be placed on those remaining. In all likelihood, that would mean poorer performance from the bullpen because of necessary overuse.

However, when it comes to incorporating Ohtani into the mix, roster construction wouldn’t be nearly the problem that it would under a typical six-man staff. Ohtani’s offensive capability is expected to allow him to be frequently used as a designated hitter. He’s played the outfield before too, though it remains to be seen whether or not that will be permitted going forward. Regardless, having Ohtani would allow the Yankees to reduce it’s traditional bench to three players, with Ohtani technically creating a fourth on days he is not pitching, whether he’s in the batting order or not. Those days wouldn’t be all that unlike recent seasons with Matt Holliday and Alex Rodriguez in the lineup or available off the bench, who were DH-only options that didn’t bother to bring a glove. With Ohtani, the Yankees would avoid having a short bullpen or bench thanks to his versatility.

What about the playoffs?

There are a couple of considerations when it comes to postseason baseball: one, will a six-man rotation result in livelier arms in the playoffs; and two, would it be difficult to revert to four days of rest during crunch time?

With fewer innings from April through September, it seems reasonable to expect fresher pitchers in the playoffs. Does that mean better pitchers? That’s a mystery. However, and perhaps more importantly, given what we know about the health effects of extra rest, fewer innings would make it more likely that a team’s best pitchers would be available come October. Having a team’s best pitchers not on the disabled list for the most important games of the season seems like a pretty important thing, and a six-man rotation makes that more plausible.

They way starters are deployed in the postseason could pose a problem, though. In the playoffs, teams generally use four starters. However, with additional scheduled days off during playoff series, teams can still give starters a full four days of rest between starts despite taking one pitcher out of the rotation. In reducing a rotation from six to four, however, a rest issue crops up. Pitchers would have to adjust from five days of rest to four upon the flip of the calendar. Although Carleton didn’t find much difference in pitcher ability when comparing four or five days of rest, his study isn’t from an environment switching to shorter rest periods, but rather of pitchers gaining a day. From a different Carleton article, he found the same when comparing the four-man rotations of yore to the more modern staff. Really, we don’t know how a pitcher would react to suddenly being thrust into four days of rest from a season full of starts made following five days off.

Further, what happens when a team’s season is on the brink and it’s best starter would be needed on just three days rest? This is common practice in staving off elimination nowadays, but for pitchers used to five days of rest, it would seem like a very big ask because it would mean a reduction of two days off at the drop of a dime. That seems quite risky.

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All things considered, a six-man staff probably isn’t for every team, at least not yet. Baseball is a copycat sport (see: bullpen usage and launch angles), so it could become trendy if a team finds success with it. There are some roadblocks to succeeding with six starters, but if the Yankees land Ohtani, why not go for it? Given the team’s depth, the Yankees seem very well suited to give it a go. I’d be more hesitant if Ohtani wasn’t a two-way player, as the roster construction issue could have become problematic over a long season. Considering that pitcher performance likely wouldn’t be hampered and extra rest could be used as a health precaution, the risk seems low during the regular season. Admittedly, I have reservations about what would happen in the postseason when it comes to suddenly reducing rest, but the vast majority of the battle is making it to the postseason. Hopefully, Ohtani dons pinstripes in 2018 and thereby gives the Yankees a good reason to try six starters.

Photo credit: Noah K. Murray / USA TODAY Sports