This spring the Tampa Bay Rays announced they were going to go with a four man rotation through the first six weeks of the season. This isn’t all that unusual as April typically has more scheduled off days than any other month.

Yesterday Kevin Cash talked about the potential for it to be used throughout the season. The headlines read four man rotation. In a world where there are multiple teams talking about extended use of a six man rotation this is only natural. Pitchers aren’t going to be pitching on shorter rest than they have become accustomed.

This is a five man rotation. There will still be a “fifth starter.” It just won’t be one person. Rotation slots will be skipped and filled with bullpen days or a spot start from a starter in Durham. There will be stretches where the rotation will look like your everyday five rotation. There are stretches where it will look more like a four man rotation.

Schedule

The schedule is what makes this possible. Despite what you believe about the economic side of the latest Collective Bargaining Agreement between the MLBPA and the owners the players did get their request of more off days during the regular season. A major league season now is 187 days up from 183 days. Four extra days doesn’t sound like a lot, but going from 17 to 21 off days not counting the four day all-star break is pretty big. It’s almost one extra day off a month.

With these four extra days there will be ways to get more out of your roster. The Rays are trying to look into leveraging those extra off days into more starts from the top of your rotation.

The season starts with eight off days through May 10. The Rays will be play 35 games in 43 days. The Rays will use this to limit the use of a fifth starter. They did this in 2016 and isn’t all that uncommon around the game with the additional days off in the beginning of the season.

The Rays have seven stretches of at least ten games in a row. This will require at least two times through a rotation. Five times the Rays will play three or fewer games in a row. Eight additional times there will be only five or six games between scheduled off days.

Between May 11th and June 20th the Rays will only have two off days while playing 39 games. This is the portion of the schedule where the rotation could look more normal or the Rays could leverage their Durham starting depth as spot starters.

Gains

Leveraging the value of the 40 man roster is paramount in trying to add wins to the major league ball club. Even with Brent Honeywell and Jose De Leon going down with Tommy John Surgery the Rays have enviable depth in the rotation and bullpen.

If you start your best pitcher that is available on normal rest any night the Rays have the ability to give 36 starts to their number one, 35 starts to their number two, 34 starts to their number three, 32 starts to their number four, and 25 starts to their number five.

Instead of having 32-33 starts for every spot in the rotation the team is able to give seven starts that would normally go to their number five to the top of their rotation. Chris Archer and Blake Snell receiving an extra 3-4 starts each is a big gain. Those 15-24 innings each are going to better pitchers.

In another organization Matt Andriese, Austin Pruitt, Chih-Wei Hu, Anthony Banda, Yonny Chirinos, and Ryan Yarbrough would be battling for the fifth starter job. Instead the Rays are going to leverage this strength by giving additional innings out of the bullpen while picking up spot starts as needed.

Options are the key to making this work. Every player listed has a minor league option. Much like how the Los Dodgers used the disabled list to make sure their rotation stayed fresh the Rays will have fresh arms available to be called up at a moment’s notice.

The fifth starter is generally a weakness. Even with the depth of quality arms this is no exception for the Rays. If a player deserves more innings they are able to earn them if they are better than any of the other four options that see consistent starts.

The players who don’t start are going to see multiple inning roles out of the bullpen. The difference between the average reliever and average starter are pretty big because of the additional times through the order.

Over the past three years starters have put up a 4.30 ERA, 4.27 FIP, and 4.21 xFIP. Relievers have put up a 3.94 ERA, 4.00 FIP, and 4.09 xFIP. Over a third of a run is significant, but starters the first time through the order have put up a 3.50 ERA, 3.96 FIP, and 3.99 xFIP. Starters have actually been better than relievers their first time through. The multiple times through the order is what kills their overall numbers.

Teams need bulk innings. There will always be a place for starters. Elite starters are more valuable when you’re able to leverage extra starts out of them. Giving more innings to pitchers first time through the order should produce better results as a whole.

This won’t magically make bad pitchers good, but it will get the most out of useful MLB pitchers.

Durham 2017

We’ve already seen how this could play out in Durham last season. The Durham Bulls had 25 players make a start for their team. The breakdown of the starters for Durham last year can be found here.

Ryan Yarbrough (26), Brent Honeywell (24), and Yonny Chirinos (22) were the only starters who made more than 20 starts. Jacob Faria (11) was the only other to make more than 10. Blake Snell (7) made a run of starts when he was demoted.

Injuries was a partial cause as Taylor Guerrieri (2) and Jose De Leon (3) were expected to get more starts, but went down with prolonged injuries.

If you flip the Durham Shuttle you see the Bulls received some spot starts from Austin Pruitt (4), Chase Whitley (2), and Matt Andriese (1) filled in during rehab assignments or when they were optioned for fresh arms.

Players who were mostly used as relievers got starts. Chih-Wei Hu (4), Andrew Kittredge (2), Diego Castillo (1), and many more got starts. It looks like Hu might be groomed to excel in this role. Hu was able to give the Bulls quality innings out of the rotation and bullpen much like we have seen out of Matt Andriese during his time with the Rays.

To get away with this within the rules of roster usage the Bulls used their relieves for more than the traditional three outs most of the time. The Bulls bullpen breakdown can be found here.

Jaime Schultz was the only major contributor who pitched fewer than one inning per appearance. This likely was due to his injuries last year. As a former starter he’s a guy that can likely handle more than one inning every time out.

Even the big guns like Diego Castillo, Jose Alvarado, Ryne Stanek, and Andrew Kittredge threw more than one inning most times out.

Replacement level is different when talking AAA baseball, but the bulls were able to navigate the needs getting help from AA and some cases the MLB club when needed.

Conclusion

I’m in favor of any plan that moves innings from the back of the rotation to Chris Archer and Blake Snell as long as it isn’t abusive. This plan gets more starts out of the front without working them more than they are used to.

Will the Rays be able to add wins by leveraging the value of their whole 40 man roster? I don’t know, but it’s worth a shot. The Rays are in the part of the win curve that marginal wins could matter. If they play things like everybody expects they should they will fall short a majority of the time.

They are uniquely positioned with a wealth of arm talent and a team that should be trying everything they can to get the most out of all 40 players on the roster and not limit themselves to only 25. If the roster were a favorite for the postseason you probably wouldn’t attempt this, but that’s not where the Rays are. They have talent. They could make the playoffs with either a little fortune or extracting wins other teams haven’t been willing to take the chance to find.