He already had sprained one (when he landed on Kyrie), then kept playing and sprained the other while over compensating. At this point, it's a damned if you do, damned if you don't situation for Rose. If he'd come out after the first sprain, it'd be "welp, rose is out again". but he stayed in, and then got hit with another and sat out the next game and people were like "welp, rose sitting out again". So, he decides to play the NEXT game to shut everyone up, and he sits out this one, and people are like "welp, there goes Rose sittin' out again".
The whole thing is silly.
Edit: should have added that people were saying "well, he shouldn't have played the last game". so which is it? You want him to play, or don't you? Or do you just want to make fun of him just when he's not playing? Make up your minds.