No one could fault ESPN for wanting to hedge a bit, but what this report amounts to is that no one knows when Roethlisberger will be back. It begins by saying the Steelers are "hopeful, though hardly optimistic" that Roethlisberger will be able to play in the December 2 game, then goes on to say this:
Steelers doctors believe Roethlisberger will miss three weeks, though the team has not abandoned hope that he may miss only two games and be able to return for the rematch against the Ravens.
The reports also notes, more concretely, that Roethlisberger is still in pain. It will probably be a week or two before we have a much better idea what Roethlisberger's timetable is. If it does turn out that he misses three games, that's not the worst news for the Steelers, even though two of those games are against the Ravens. If Byron Leftwich and company can win against the Browns next week, the Steelers will still be (at least) 7-5 when Roethlisberger returns, putting them in pretty good position to make the playoffs.