We've known this all along. Rose himself thinks he can come back quicker, but that is just a bad idea. As has been discussed here..it takes a full year to recover from an ACL tear..that puts him at full recovery in May...when the Bulls would be in the 2nd round of the playoffs..if they could get that far...
Its best to just forget about this season. Its a lost season, not that the team would have competed for a title as currently constructed anyways. Miami just got a shit ton better. Let the guys rest, let the front office work its magic next offseason (we hope) and then we'll compete for that title at 100% in 2013-14.