The rulebook exists to lay out a protocol for the game of football. It never claims to be fair.
The Dolphins found as much when they apparently sealed a victory, only to have replay give the Steelers a second chance to win the game.
Steelers quarterback Ben Roethlisberger scored a go-ahead touchdown, but fumbled the ball. The play was ruled a touchdown, but replay determined that Roethlisberger, indeed, fumbled prior to scoring the touchdown (video). The Dolphins claimed a recovery of the loose ball.
However, we could not explain the ultimate ruling any better than referee Gene Steratore, trying to channel the voluminous descriptions of some of his colleagues:
After review, it has been determined that prior to the ball crossing the goal line, the runner did lose possession of the ball. However, by rule in replay, two aspects of this play must be available to be viewed. Not only did we have to view the fumble being a fumble, we also have to have clear evidence of the team recovering the ball.
After review, we do not have clear evidence of the defense recovering the football. Therefore, Pittsburgh will have the ball, fourth and goal at the half-yard line. Miami will not be charged with a timeout, and the clock will start on the ready-for-play [signal].
My initial reaction is that the spot of the ball is incorrect. We know the ball was determined to have been fumbled, because the touchdown was overturned. Since we don’t have a conclusive recovery (according to replay rules), the ball is ruled dead at the point when there was a touchdown signal, regardless if there was a whistle. So the loose ball is ruled dead in the end zone, and the offense is responsible for putting the loose ball in the end zone, therefore, the correct ruling should be touchback, Dolphins ball.
There was a similar circumstance last year where replay determined the ball to be dead after touching an out-of-bounds player in the end zone. The result was a touchback for the other team.
Apparently, that reasoning only applies when the ball is out of bounds, not loose and dead in the end zone. Also, if you don’t recover your own team’s forward fumble (like when it goes out of bounds), the ball goes back to the spot of the fumble. (Update 10/30: Specific rules are cited in the comments by popular demand.)
And credit to Steratore for making the correct call, even though your gut might tell you the ruling would be otherwise.