Considering there's 2 days off between Game 1 (Monday) and Game 2 (Thursday), if I'm the C's, I play it cautious and sit Jaylen for Game 1. It sucks, but honestly I think overall we dodged a bullet as most have alluded to here, and there's still a chance we get Jaylen from Game 2 onwards (at 70% health or better).
Unfortunately it might mean losing Game 1 as a result, but in the long run it's the wise move.
But hey, the C's have surprised me all year long and so if they win Game 1 on Monday W/O Brown, that would just be something else! But it will take herculean efforts again from guys like Horford, Rozier again I believe to be honest. (And Tatum, Morris - basically can't have too many guys struggling)