I'm not sure how much of an upgrade Lin would be on VanVleet, but he should replace what they were getting from Delon Wright before trading him.
I don't see any reason to find doom for the Celtics in the news that the Raptors added Jeremy Lin off a buyout.
With that said, after each move that the Celts' Eastern Conference competitors make to improve their roster for the post-season, I can't help feeling that this season is already, on some level, over for the Celtics.
They will go through the motions and perhaps win a playoff series, but the next major development for the Celtics franchise won't happen until they can officially engage in trade discussions for Anthony Davis.
I know that there are plenty of reasons to think that this Celtics team is good enough as constructed to play exciting basketball in April and May.
But so far this season I haven't seen much to make me think that the Celts really believe in this team as it is currently constructed. Half the guys on the roster seem like they'd be happier on a different team in a different role. Meanwhile the East is much stronger than last year and multiple teams above the Celtics in the standings are sharpening their weapons for the battles to come in the playoffs.