I don't know if that is right. I found this: "3. As long as the player did not appear in a game during the retroactive period (including "official" MLB Cactus League or Grapefruit League games or other MLB pre-season exhibition games), an MLB 10-day DL assignment can be backdated up to three days." https://www.thecubreporter.com/book/export/html/3538 there is no limit to how far back they can go. http://m.mlb.com/glossary/injuries/10-day-dl Players may be placed on the 10-day DL "retroactively," meaning the DL stint is backdated to the day after the last date on which the player appeared in a game. For instance, if a pitcher is diagnosed with elbow inflammation on June 4 after feeling soreness during his June 1 start, he could be placed on the 10-day DL on June 4 retroactive to June 2. In that case, he would be eligible to return from the disabled list on June 12. I saw that as well, but it doesn't actually say anything about a retroactive limit, and the examples they use are only 1 or 2-day instances. I think there is a limit, though. I don't know if the link I posted is 100% correct. but I am almost certain there is a limit to how far back you can backdate a DL stint.