At Florida Brown was a rush specialist, but his transition to the pros wasn't easy. Although, the former Gator played the run better than anyone expected, he wasn't brought to Chicago to contain the backside. The Bears already had Bryan Robinson in that capacity and he's now moving inside to help with the run defense.
The coaching staff can hope for a smoother NFL jump for Michael Haynes. He isn't expected to be a fulltime player as a rookie, but the first-round pick will definitely be counted on in third down and nickel situations.
If the pass rush isn't consistent then the defense's true weakness will be exposed. The secondary isn't good enough to cover opposing wide receivers for more than a few seconds. It got so bad last year that the group had to try to defend wideouts for five seconds. If that's the case this year then the Bears will not grace the new Soldier Field with a winning campaign.