I just upgraded from 2019 to the 2021 version. It looks fantastic of course. But I'm looking at my team's roster and their ratings. And I know what all of the ratings abbreviations stand for except the DI. And I know I'm going to feel like a moron as soon as somebody tells me, but I haven't been able to find it in help or anything. So here I am begging somebody to make me feel stupid and remind me what it stands for lol

It's their discipline rating, which I'm assuming affects their foul tendencies during games etc.