From the Athletic:
Should MLB go back to a 15-day injured list? — Anthony F.
I often find myself going back and forth on this question. In a lot of ways a 15-day IL makes more sense. Players are forced to take more time when recovering from an injury, which is often a good thing from a medical perspective. Ten days isn’t usually quite enough time when coming back from something like a minor hamstring strain, and those extra five days can make a big difference. It also prevents teams from abusing the IL when a player is out of options and can’t be sent down to the minors. Teams were much more hesitant to use the IL to manipulate their roster, especially with pitchers.
On the flip side, the 10-day IL has its advantages because teams are less likely to try to hold a guy out for a few days and hope they can recover. If it’s a minor injury, there is a big difference between a guy being forced to miss 10 days vs. 15 days. Ten days doesn’t sound so bad, so teams may take a more cautious approach and place them on the IL.
Ultimately, I think the 15-day IL was slightly better and made more sense from a medical perspective, but I see both sides here