The Brave New World of the 10-Day DL

Back when I first became a baseball fan in 1960, a player placed on the MLB Disabled List was required to remain on the DL for a minimum of 30 days, there was no "backdating" of a DL assignment, no more than two players could be on the 30-day DL at any one time (any additional players would have to be placed on the 60-day "emergency" DL or transferred from the 30-day DL to the 60-day DL), and there was no such thing as a minor league rehabilitation assignment for players on the DL (position players on the DL would get back into playing shape by taking BP and fielding practice and pitchers got back into shape by throwing bullpen side-sessions and "live" BP, and after being reinstated from the DL, starting pitchers would temporarily work out of the bullpen while building-up endurance and arm strength).

The 30-day DL limit was reduced to 21 days in the mid-1960's, a 15-day "supplemental" DL (one position player permitted to be on the 15-day DL at any one time) was introduced and the maximum number of players permitted to be on the 21-day DL was increased from two to three in the early 1970's, and the "emergency" DL limit was temporarily reduced from 60 days to 45 days for a time in the 1970's.

A 30-day "overflow" DL (maximum of one player, could be used only when the 15-day and 21-day Disabled Lists were full) was added in the early 1980's, and the 15-day supplemental DL limit was expanded (maximum of two players could now be on the 15-day supplemental DL at any one time, of which only one could be a pitcher) and Minor League rehab assignments were introduced in 1985.

The 21-day DL and the restriction on the number of players who could be on the 15-day DL at any one time were eliminated in 1991, and the 7-day "concussion" DL was added in 2011.

As part of the new Collective Bargaining Agreement that was ratified this past December, MLB will be going to a 10-day minimum Disabled List from the old 15-day DL beginning with the 2017 season. As a result, the starting rotation at a club's AAA affiliate becomes more important than was previously the case. It now becomes important to have at least five MLB-ready starters at AAA who can be recalled from (and then optioned back to) the AAA affiliate at the drop of a hat.

For the Cubs, that probably means a starting rotation at AAA Iowa of some combination of Rob Zastryzny, Eddie Butler, Jake Buchanan, Aaron Brooks, Casey Kelly, and/or Williams Perez. That is, five (or even six) MLB-ready starting pitchers who are already on the MLB 40-man roster (Zastryzny, Butler, Buchanan, and Brooks) or who can be added to the 40 but who have minor league options left if they are added (Kelly and Perez).

For example, let's say John Lackey tweaks something in his start on Sunday, but it's just a minor "day-to-day" thing (finger blister, back twinge, quad tweak, et al), not something that would warrant an immediate trip to the DL. The Cubs play Monday, Tuesday, and Wednesday, and have a day off on Thursday, and so Lackey's next scheduled start is the following Saturday. He skips his bullpen side-session on Tuesday, and remains questionable for his next start. 

In past seasons the Cubs would either keep Lackey on the Active List and just skip his rotation slot if he is unable to make his next scheduled start -- going with a "bullpen day" on Saturday instead -- or else place him on the 15-day DL and cause him to miss two starts instead of just one. And if he is kept on the Active List while missing a start, that would put a strain on the bullpen for the entire weekend series and force the manager to go at least a week with essentially a 24-man roster .

But with the new 10-day DL, Lackey could miss just one start, and the Cubs would not have go with a "bullpen day" to cover Lackey's one missed start.

Here's how it would work in practice:

Lackey is questionable for his next start, so he remains on the Active List going into the weekend series. But on Friday (the day before Lackey's next scheduled start), the Cubs call-up whichever Iowa starting pitcher is scheduled to pitch on Saturday (let's say it's Eddie Butler), and place that pitcher on the Taxi Squad. NOTE: A club can recall a player from a minor league Optional Assignment and place the player on its "Taxi Squad" for one day. If the player is not added to his club's MLB Active List by 3 PM (Eastern) the next day or at least three hours prior to the scheduled start of the next day's game (whichever is later), the player must be removed from the Taxi Squad and returned to his minor league assignment. A player on the Taxi Squad does not count against his club's MLB Active List, and the player does not accrue MLB Service Time while on the Taxi Squad. The most common reason to recall a player and place him on the Taxi Squad is when a club is considering whether to place a player on the Disabled List but has not yet decided.

Then on Saturday (before the game) the Cubs determine that Lackey will not be able to start that day, and Butler (the pitcher who was called-up and placed on the Taxi Squad on Friday) is officially recalled from his optional assignment and inserted into Saturday's starting lineup as the starting pitcher, and Lackey is placed on the 10-day DL retroactive to the previous Monday (he last pitched on Sunday), making him eligible to be reinstated from the DL the next Thursday, just in time for his next scheduled start. In fact, after Butler (the "6th starter") makes his start on Saturday, he could be immediately optioned back to Iowa on Sunday and replaced by an Iowa relief pitcher for a few days (if it's for sure that Lackey won't miss any more starts), until Lackey is eligible to be reinstated from the DL on Thursday.

So the new MLB 10-day DL will allow clubs to be cautious with a starting pitcher who incurs a minor injury in a start, without having the pitcher miss more than one start. With the 15-day DL, a starting pitcher who was placed on the DL with a minor injury would miss at least two starts, or else the club would have to keep the pitcher on the Active List (25-man roster) through the pitcher's one missed start and go with a "bullpen day," effectively leaving the manager with a 24-man roster for ten days.

While the new MLB 10-day DL will mostly impact a club's decision to place starting pitchers on the DL, it will have an effect on a club deciding to place a relief pitcher or a position player with a minor injury on the DL as well. That's why it will be even more important than was the case previously to have players on the MLB 40-man roster who can actually help at the big league level and then can be optioned back to AAA when the injured player is reinstated. That makes "support players" who are out of minor league options (like Matt Szczur, for example) less-valuable than they previously were. A club will need to use the 40-man roster as a constant feeder for the 25-man roster throughout the season as players are placed on the 10-day DL, and that requires having players on the 40-man roster who can easily be sent back & forth to AAA (riding the "Des Moises - Chicago shuttle").

So while the MLB/MLBPA did not agree to go with a 26-man roster in 2017, the 10-day DL should result in a de facto 26-man roster because of the expected increase in short-term DL assignments. It's just that the "26th man" will change from week to week. (The "26th man" might be a starting pitcher one week, then maybe a catcher the next week, then a relief pitcher the week after that, etc).