Roethlisberger did say Smith-Schuster deserved to be fined for the play, though mostly because of how he taunted Burfict after the hit rather than for the collision itself.
Jon Runyan, the NFL's vice president of football operations, ruled that Smith-Schuster "delivered a violent and unnecessary blindside shot to (Burfict's) head and neck area". Gronkowski was also suspended one game for intentionally falling down on top of Buffalo Bills cornerback Tre'Davious White and striking him in the back of the head.
Smith-Schuster added extra attention to the play by standing over an injured Burfict, who has a history of concussions as well as unsafe hits and actions that have drawn the ire of the league office.
There's not a set rule for what gets a player suspended.
"I didn't know it was Burfict at first". Asked if any plays from the Bengals bothered him, he said he was focused on "the nature in which [his players] perform" and trusts Cincinnati coach Marvin Lewis to do the same. I thought what happened, the play that happened, happened in the context of a football play.
In a letter to Smith-Schuster, NFL Vice President of Football Operations Jon Runyan wrote: "You are suspended for the unsafe and unsportsmanlike acts you committed during the fourth quarter of last night's game".
Smith-Schuster apologized for the hit during post-game interviews as well as on Twitter. "Praying he gets better". He was flagged for unsportsmanlike conduct and taunting. Brown was deemed to be a defenseless receiver at the time of the hit.
"I didn't think it was warranted, I thought maybe a fine", Roethlisberger said of Smith-Schuster's discipline. I apologize for standing over him and that isn't me.
He ended up receiving two penalties on the play, one for the hit against a defenseless player, and the other for taunting.