Have we seen Jackson play an Nba game?
Of course not. But the point is not that Jackson comes in and becomes Marcus Smart. If the Celtics believe Rozier, and to a lesser degree Jackson (who they'd then want to sign right now), are ready to play NBA minutes, I just don't see a tremendous drop off in their defensive efficiency. And I just don't see how the Cs can carry Thomas, Smart, Bradley, Rozier, Hunter, and Jackson on the same team. Maybe they will, but I'd prefer they don't.
If Smart doesn't improve offensively this year, his value will begin to drop off. To me, he represents the most obvious chip to move in an effort to get a starter quality big this summer. In other words, there's risk in banking on Rozier and / or Jackson, but there's also risk in keeping Smart.