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Does a four man rotation make sense in Philadelphia?

With Tampa Bay utilizing the concept for the first month of the season and maybe beyond, might the Phillies consider doing the same?

MLB: Spring Training-Philadelphia Phillies at Toronto Blue Jays Butch Dill-USA TODAY Sports

This past week, manager Kevin Cash of the Tampa Bay Rays discussed his team’s plans for using a four man rotation to begin the season, even how the team is considering using it throughout the entire season if possible. It’s a move that hearkens back to the old days when men were men and threw every fourth day instead of every fifth, when pitchers completed their own games, when....yeah, that’s good enough. As our colleagues at DRaysBay mentioned in their analysis, the extra four off days off during the season agreed on by owners and the MLBPA will stretch out the schedule ever so much, making this decision, especially in April, a more plausible one than it ever was before. Whether this decision was brought about by research or the fact that Tampa Bay just lost two of its top pitching prospects to the Tommy John scourge is up for debate, but any way you look at it, it is interesting. Interesting enough to make you wonder: would the Phillies consider this option as well?

On paper, the rotation for the Phillies looks to be the “weakest” point of the roster. Now, “weakest” here is completely subjective. After all, Aaron Nola sits atop as the team’s ace, followed by Jerad Eickhoff, Vince Velasquez and at this point, Jake Arrieta. He’ll need some time to get ready to throw in games, so we’ll pencil him in to the fourth spot, meaning he won’t be needed until the Monday after Easter. The pessimist will note that Eickhoff is coming off of an injury-marred season, Velasquez has yet to show any kind of the hallmarks of being a starter in this league (consistency and durability) and Arrieta, as accomplished as he is, has seen his numbers dip the past two seasons. It’s a good rotation, but even still, there are as many questions as there are certainties.

What doesn’t have too many question marks is the bullpen. Since Matt Klentak added to it this winter, the bullpen looks like it could be one of the better units in baseball. Kapler has already said that bullpen usage will depend on the situation, meaning players will have to adjust to being used at times they may not have been in the past. So, the deployment of these players will bear watching as the season wears on. It brings about a theory that has been bandied about in the past: if the bullpen is so much better, why not use it more? Of course we know that using a bullpen too much will wear them down as the season goes on, so we don’t want to see Kapler going to the ‘pen too much, but it makes sense to use them more often if they are there.

So, we’re left at a philosophical crossroads. Does the team want to utilize its stronger asset (the bullpen) more often, risking their collective health over the course of a season, or simply do it the way they’ve always done it, going with five starters as usual? Let’s look at the pros and cons of each decision.


With the schedule falling the way it does during the first month of the season, there really isn’t much need for a fifth starter as it is. What I did was, using a calendar, pencil Nola, Eickhoff, Velasquez and Arrieta in as the top four starters and put them in a rotation. Here is what the season looks like until May 3 (pardon the poor quality picture/calendar):

Now, I will preface this by saying that I am unsure if Arrieta will be ready by that starting date. I’ll just assume that he is. As you can see, there are enough off days where if the team chooses to use a four man rotation, there will only need to be a “bullpen game” twice. Since Mark Leiter looks to be the best candidate for the job, we can give each of these games to him. Each starter would receive his normal four days of rest save for one instance each toward the end of April. Even then, the team could only ask each guy to throw 4-5 innings since there is a fully stocked bullpen to utilize. Using this type of rotation wouldn’t stress the starters as much as I thought it would since they are rarely on short rest.

A four man rotation also wouldn’t necessarily impede Arrieta’s journey toward getting ready for the season. In the calendar above, we have him starting his first game on April 2, a long shot considering he’s only got three weeks to get there. However, if he is able to make that first scheduled start on time, he is not being asked to do anything out of the ordinary from that start forward. Only once is he asked to go on short rest, but that is followed by an off day. He’d be able to get back into his normal routine right away. He would, presumably, be up to speed at that point, so the risk of injury would be lessened.

Finally, the idea of having your best starters throw the most innings could help the Phillies get some extra wins in April as they march toward the middle of the season. While a lot of people worry about wins in September and October when it comes to playoff baseball, as they say, the wins in April count just as much. We aren’t sure what kind of team they have now, but if they are serious about making some kind of push toward the playoffs, getting every win counts. Having your best starters throw most often would help with that.


Of course, there are multiple cons to this idea as well. The first is the sheer amount of innings you would be asking your top four starters to be throwing. Let’s say, for instance, that the Phillies use the four man rotation to great success in April and wish to keep it going. As you saw from the calendar, each starter would be making at least 7 starts before May 3 (Nola would make 8). If each keeps up that pace and throws, let’s say, 5 13 innings on average, that’s about 37 innings. If that pace continues for the rest of the season, they would be asking each guy to throw ~220 innings in 2018. That’s assuming perfect health, never missing a start, etc. That is a LOT of innings to ask your rotation to shoulder over the entire season. Especially when you have these as career highs:

  • Nola: 168 innings
  • Eickhoff: 197 13 innings
  • Velasquez: 131 innings

In Arrieta’s case, look at the trajectory of innings thrown he has been on: 229 IP in 2015, 197 13 IP in 2016, 168 13 IP in 2017. These aren’t exactly reassuring numbers from any of the rotation members, especially when this team has playoff aspirations.

That doesn’t begin to talk about the innings they’d be putting on the bullpen. If we have starters only able to go 5 13 innings on average each night, now the bullpen has to account for anywhere from 3-4 innings per night. Over 162 games, that’s <grabs abacus> 648 innings over the season, again, not accounting for any injuries. The bullpen is good, but can they account for that many effective innings?

The team would also be asking the starters to, at times, pitch on short rest (short rest here begin defined as less than four days). None of Nola, Eickhoff or Velasquez have thrown on less than four days rest as a starter. Surprisingly, neither has Arrieta! While he has done so as a reliever, he has never, according to Baseball Reference, started on less than four days’s rest. That kind of shocked me, but it probably shouldn’t. Asking these starters to go on three days’ rest so early in a season in which they have playoff hopes is foolhardy, especially when they have perfectly fine options waiting in Lehigh Valley who are capable to joining the rotation as a fifth starter.

Starting pitchers on short rest would also be bucking a league wide trend to not have their starters go on less than four days of recovery. Last year:

Only 71 games were started by pitchers going on less than four days’ rest. We can reasonably surmise that a team that is trying to be as analytically forward as the Phillies are trying to be will not be doing something as “old school” as this. Plus, this type of reasoning seems to go directly against what Kapler has been preaching all spring about getting enough rest and recovery time, even during the leisurely days of spring. Couple that with the fact that both Eickhoff and Velasquez are coming back from an injury shortened season, and it is HIGHLY doubtful the team would allow this trend to continue past May 3.


Yeah, it ain’t happening. There is little reason to have these four starters and ONLY these four starters continue to rack up this amount of innings at any point in the season. You can make the argument that it really isn’t much of a stretch to be doing so in April, but past that would go against pretty much everything this management team believes in. Yes, you can theoretically get away with it for the first few weeks, but at what cost? Are we really hoping that the team stretches its young arms so early in the year?

With the signing of Arrieta, the signal has been sent that playoff aspirations have been ratcheted up. Getting to September with not only a tired rotation, but a tired bullpen as well is a recipe for a very early exit. As enticing as it may seem to ride those top four starters as much as possible, there is no real reason to do so.