Chatwood to the DL Sure Sounds Like a Good Idea...
Every now & then I see someone suggest the Cubs should just put Tyler Chatwood on the DL so that he doesn't take-up a spot on the 25-man roster from a pitcher who would be more-useful to Maddon and the Cubs. The problem is,
a club cannot place a player on an MLB DL unless the club physician signs off on it - AND - (where there is no physical evidence to corroborate the diagnosis) the player consents (or"plays along," so to speak).
So an MLB DL assignment requires either some tangible confirmation evidence of injury (like an x-ray or MRI) or illness (blood test) to justify the DL assignment, or the player has to claim an injury (like "my shoulder is stiff," or "my calf hurts," or "my back is tight"). If there is no physical evidence of injury or illness and the player does not claim an injury, the club cannot place a player on an MLB DL. The club cannot compel the player to claim an injury or an illness. In the case of struggling LHRP Brian Duensing, the Cubs might have said something like "we can trade you to Texas as part of the Hamels deal, but we can't if you have an injury that will keep you from rendering service for a while." But the Cubs could not compel Duensing to claim that he had a sore shoulder. It would have been entirely up to Duensing to go to the team doctor and make the complaint.
Also, for a player on an MLB 10-day DL, the injury or illness must be re-certified by the club physician every ten days. Again, this would require cooperation from the player if the injury or illness cannot be confirmed by physical evidence.
If a player is on an MLB 10-day DL but is no longer complaining of pain or stiffness, the player cannot remain on the DL unless he is on a minor league rehab assignment, and then the player can unilaterally decide when the rehab assignment is over (up to a maximum of 30 days for a pitcher or up to 21 days for a position player, although a minor league rehab assignment can be renewed once for pitchers or players rehabbing from TJS). So if a player remains on a minor league rehab assignment even after he is 100% back in shape, it has to be 100% the player's decision to remain on the assignment.
So in the case of RHRP Anthony Bass (for example), he could tell the Cubs at any time ("I feel great and my rehab is over and I'm ready to rejoin the MLB club"), and if he does that the Cubs are stuck. Bass is out of minor league options, so the Cubs would either have to reinstate him from the DL immediately or -- if there is no room for him on the 25-man roster -- DFA him and place him on Outright Assignment Waivers (which are irrevocable) and risk losing him off waivers (which would probably happen).
But from Bass's POV (and with his agent's advice) he probably realizes this, and he doesn't want to be claimed by KC, or Miami, or San Diego, or Baltimore. He knows Maddon likes him and has confidence in him and so quite naturally he would prefer to remain with the Cubs and have a chance to pitch in the post-season (or at least in meaningful games in September), so he doesn't pull the "reinstate me or waive me" card, He just keeps his mouth shut and remains on his rehab assignment at Iowa, where he is paid his MLB salary and receives his MLB per diem and accrues MLB Service Time while patiently waiting for a spot on the 25 to open up, either by virtue of another pitcher going on the DL with an injury in the next few days, or when Active List rosters expand on September 1st (whichever comes first).
It's different for a player on an MLB 60-day DL, especially in the case of transferring a player who is already on the 10-day to the 60-day DL. The club physician is not requred to re-certify a player's injury or illness every ten days once the player is on the 60-day DL.
So (for example), even if RHRP Justin Hancock (who went on the Cubs MLB 10-day DL on June 26th with a right shoulder strain and then was transferred to the 60-day DL on July 31st) is 100% healthy, he must remain on the Cubs MLB 60-day DL until he has spent at least 60 days on the DL (or even longer if he is on a minor league rehab assignment, as long as his rehab assignment has not expired). Also, Hancock (or his agent) would know that while he is on the 60-day DL he is paid his MLB salary and MLB per diem and accrues MLB Service Time, whereas if he was reinstated from the DL he would be optioned to Iowa and be paid his minor league split salary (which in his case is about about 1/10 of his MLB salary) and not accrue MLB Service Time or receive his MLB per diem. So he would be smart to keep his mouth shut, disappear, and just quietly remain on the 60-day DL for the rest of the season, especially if there is no clear path for him to the Cubs post-season roster.
Not requiring re-certification by the club physician every ten days is also why the Cubs will probably recall Adbert Alzolay (who is on the AAA Iowa 7-day DL with a lat strain) from his minor league optional assignment and place him on the MLB 60-day DL on September 1st (to open up an additional spot on the 40-man roster for Chris Gimenez, Drew Smyly, or Yu Darvish). Once Alzolay is on the Cubs MLB 60-day DL, he would stay on the DL until the conclusion of the World Series and a physician's re-certification of disability would not be required every ten days.
However, because days spent on a minor league DL do not do not count toward the minimum number of days a player must spend on the MLB 60-day DL, Alzolay would have to spend at least 60 days on the DL before he could be reinstated. And since a player cannot participate in the Arizona Fall League while he is on the 60-day DL, Alzolay would not be able to pitch in the AFL until at least October 31st (which is about 2/3 of the way through the AFL schedule) since he could not be reinstated from the 60-day DL until he has spent at least 60 days on the list, so he would probably have to get his "make-up for lost 2018 innings reps" at post-season AZ Instructs instead.
BTW, the DL works a bit differently in the minor leagues...
If a minor league team wants to place a player on the 7-day DL (which is the minor league's version of the MLB 10-day DL), the club just has to notify the league office (the Carolina League office for Myrtle Beach, the PCL league office for Iowa, etc) that a player is unable to render service and the player goes on the DL. A certification form signed by the club physician is not required and the MLB Commissioner is not involved. That's why you see certain players bounce back & forth/on & off a minor league 7-day DL throughout the course of a minor league season, especially players who are kept around as "roster depth" (a third catcher, a 5th outfielder, a second utility guy, a 6th or 7th SP, or an extra man in the bullpen). As long as the player does not protest, the DL assignment is all good.
And from the player's POV, the club will say "you can go on the DL or we can give you your release... your choice." And of course most minor league players (especially the ones who are just hanging-on as roster depth) will be more than agreeable to a somewhat murky DL assignment (which is why a minor league 7-day DL assignment is sometimes called the "phantom DL"). In fact some free-agents who are signed as minor league organizational depth during the off-season sign their contract knowing that is how they will be used, moving back & forth between the 7-day DL and the active roster (as needs arise), and maybe serve as 1st base coach or bullpen catcher or maybe throw BP while waiting to be reinstated. And they are OK with that.
Also, unlike players on an MLB DL, minor league players cannot refuse a rehab assignment and cannot terminate the assignment unilaterally, and a player on a DL of a full-season affiliate can only be sent on a rehab assignment to a short-season affiliate (in the case of the Cubs, that would be Eugene, AZL Cubs #1, or AZL Cubs #2, but not "Foreign Rookie" affiliates DSL Cubs #1 or DSL Cubs #2). So for example, a player on the Iowa 7-day DL cannot be sent on a rehab assignment to AA Tennessee or to Hi-A Myrtle Beach. Players on the DL at Iowa, Tennessee, Myrtle Beach, or South Bend can only be sent to Eugene, AZL Cubs #1, AZL Cubs #2 for their rehab assignment. And there are no rehab assignments for minor leaguers prior to the start of the short-season leagues in June. Rather, a player on a minor league DL who is rehabbing is assigned to Extended Spring Training (which is not considered an official rehab assignment, so there is no max time-limit on a player rehabbing at Extended Spring Training, other than the end of EXST and the start of the short-season leagues in June).