As we all know, replacing a legendary broadcaster isn't easy — and certainly won't be for the Dodgers on that sad, hopefully far-off day after Vin Scully has called his last game for the team.Craig Calcaterra of Hardball Talk subscribes to the theory that maybe a rotating set of broadcasters is better in the immediate aftermath of a legend's departure, rather than asking one person to bear the burden of walking in his microphonesteps.  So do the Seattle Mariners, who will rotate five men through their radio booth at various times in 2011, their first year without the late Dave Niehaus.One of those men will be KABC AM 790 Dodger Talk co-host Ken Levine, who returns to Seattle, where he did play-by-play in the 1990s. Levine says that it's not clear whether his new part