Major League Baseball teams were slow to evolve to the fixed five-man rotation. For a long time, the trend was to skip the fifth starter whenever possible in order to give the top pitchers more starts.
In 1976, 32 pitchers made more than 33 starts—the number of turns that the first two men in the rotation would get if the team stayed in a fixed five-man rotation all year—while two of them led the league with 40 starts. In 1986, 29 pitchers made more than 33 starts, with two topping out at 39 starts. Thirty pitchers made more than 33 starts in 1996, with two making 36. In 2006, the number of pitchers getting more than 33 starts fell to 17, with five taking 35 turns. In 2016, the number of pitchers getting extra starts hit an all-time low of five, with only David Price taking 35 turns.
Undeniably, the trend has been to give pitchers more rest between starts. Expanding rotations to six has often been discussed, with many teams opting to occasionally insert a sixth starter. There are a number of issues that have prevented any team from going to a permanent six-man rotation, primarily the roster size and the way that rosters are currently managed. With bullpens having evolved into a large group of one-inning specialists and benches having shrunk to a bare minimum, it's difficult for teams to find a spot on the roster for a sixth starter.
The 2017 Yankees certainly fall into this category. With an eight-man bullpen and only three men on the bench, the Yankees have an additional impediment in that they have a roster spot reserved for a designated hitter.
Despite all this, the Yankees could—and should—go to a six-man rotation. They should do it now, and they should stick with it for the remainder of the 2017 season. The team has a number of issues which outweigh the inconveniences of managing a roster to include a sixth starter.
1. Masahiro Tanaka and CC Sabathia pitch better on extra rest
It is well known that Masahiro Tanaka pitches more effectively on longer rest. This stems from his days spent pitching professionally in Japan, where starters only pitch once per week. Here are Tanaka's stats from 2016 and 2017 pitching on various days of rest (the first start of each season is not included):
Masahiro Tanaka 2016-2017
|Days of Rest||GS||W-L||ERA||WHIP||BA||OBP||SLG||OPS|
|Days of Rest||GS||W-L||ERA||WHIP||BA||OBP||SLG||OPS|
Since the start of the 2016 season, CC Sabathia has also pitched better on extra rest.
The Yankees have 115 games remaining, so switching to a six-man rotation now would leave Tanaka and Sabathia with 19 more starts each. Half of those starts would be made on five days of rest, with the other half being made on six or more days of rest. Having Tanaka and Sabathia pitch less often, but more effectively, would undoubtedly help the Yankees remain competitive this season.
2. Jordan Montgomery and Luis Severino are facing an innings limit
The Yankees have not announced anything yet, but this is certainly looming.
Jordan Montgomery had only thrown 292 2/3 innings in his professional career entering the 2017 season. He threw a single-season career-high of 139 1/3 innings in the minors last year. Pitching in a five-man rotation, he is projected to eclipse his career high on or about August 16, and would reach 162 innings pitched on September 1. If the Yankees switch to a six-man rotation now, then Montgomery would not reach his career high until September 1 and would not hit 162 innings until his last start of the season on September 25.
Luis Severino has thrown 534 1/3 innings in his professional career, hurling a single-season career-high of 161 2/3 innings in 2015 and 151 1/3 innings last season. So concerns about Severino's innings in 2017 are not as dire as Montgomery's, but they will still be an issue towards the end of the year. Severino has averaged 6.11 innings per start so far in 2017, putting him on pace to pitch 196 innings this season. If he goes just a little bit deeper into games and begins averaging seven innings per start, then he would hit 216 innings on the year. Pitching 216 innings would represent a big jump from last season and his career high, so it would likely make Severino unavailable to pitch in the playoffs if the Yankees make it.
Switching to a six-man rotation now would certainly extend Severino's season and allow him to be available to start in the postseason without going beyond a reasonable increase from last's season's innings total.
Clubs have tried various things in order to try to protect the arms of their young pitchers by limiting their innings. We've seen skipped starts, pitchers pulled from starts early, pitchers moved to the bullpen, and pitchers shut down completely in September. We endured the infamous "Joba Rules" and saw Stephen Strasburg shut down prior to the playoffs. None of these things worked very well, if at all. We haven't seen a team go to a six-man rotation early in the season and stick with it. It's time for the Yankees to do that.
3. Chad Green is ready.
Chad Green pitched very well during the fifth-starter competition this spring. He did nothing wrong, and you could make the argument that he deserved the spot just as much as Jordan Montgomery. Green has pitched well in the minors this year, showed promise in the rotation with the big league club last year, and has pitched well out of the bullpen this year. Now is a good time to insert him into the rotation.
4. Next year's rotation is a big question mark.
With CC Sabathia and Michael Pineda becoming free agents, and Masahiro Tanaka possibly joining them if he exercises his opt-out clause, the Yankees could enter the offseason needing to fill several spots in the rotation.
I like the idea of getting an extended look at an additional young starter now and for the remainder of this season. The free agent pitching class will be thin this offseason. If the Yankees head into it with Luis Severino, Jordan Montgomery, and Chad Green solidified in the 2018 rotation due to good performances this year, then it makes the hot stove period much more manageable.
The Yankees have too many reasons to go to a six-man rotation now. They have no compelling reason to shy away from it. The bullpen can be managed by using the 40-man roster like the team has done in the past. This could be a positive, not a negative, as it will give additional young players an opportunity to make their mark in The Show.