When you watch a Yankee game it is impossible to know who is going to be doing the game. Usually Michael Kay is doing the play by play. On any given game the other chair could be David Cone, Ken Singleton, John Flaherty, Paul O’Neil or Al Leiter. The Mets seem to have about the same thing going on too. When I was a kid I remembered the same guys doing the broadcasts for the entire year. This seems to be a recent development. Do other markets have the same thing going on or do most have the traditional 2 guys in the booth for 162 games?
Back in the 1980’s, the Braves had 4 play by play men. Two on the radio and two WTBS. After five innings, they switched up.
Pete Van Wieren
Skip Caray
Ernie Johnson, Sr.
John Sterling
I think John Sterling went to the Yankees sometime in the late 80’s or early 90’s. IMO, he was the worst announcer of the four. I used to call him John Pewter.
I was only mentioning TV. I remember that in the past both the Yanks and the Mets had some of their announcers doing double duty with the radio. That is no longer the case. On TV they have the revolving announcers. On radio John Sterling does the play by play for every inning of every game. Susan Waldman does… well she does something. I though Sterling was good when he was teamed up with Michael Kay on the radio. They were equals. They switched off PbP duties. When Kay went to TV and his ESPN radio show Sterling became THE VOICE OF THE YANKEES. It seems to have gone to his head.
Sounds like the Yankees spent a lot of money on broadcast talent and have to employ them all somehow. 
The Cubs used to split the announcers between the radio and TV booth back in the Harry Caray days (Harry would do the 4-6 innings on radio). Thom Brennaman and Dwayne Staats were the non-Harry guys in my youth. But nowadays Pat Hughes & Ron Santo are exclusive to the radio, though Pat gets to take an inning off each day.
The Mets in the 60s used to rotate announcers among Ralph Kiner, Lindsay Nelson, and Bob Murphy. They’d switch during the game, and all three did radio, too. There was usually only one announcer at a time for both radio and TV broadcasts. Kiner usually left after the sixth inning to prepare for his postgame show. So a rotation might be:
Innings 1-3 – Kiner on radio, Murphy on TV
Innings 3-6 – Nelson on radio, Kiner on TV
Innings 7-9 – Murphy on radio, Nelson on TV
Later, Murphy did radio and Kiner and Nelson split the TV duties.
She provides sound clips for the amusement of Boston talk radio listeners. “Oh, my goodness gracious!” 
It’s a little different for the Red Sox this year, who have a variety of color men matched with Don Orsillo while Jerry Remy recuperates from cancer treatments. I’ve actually enjoyed that, especially when it’s Dennis Eckersley.
God I haven’t. I want my Rem-Dawg back.
Although it was pretty hilarious when Eck said “shit” live on the air.
I just checked the Sports Net NY page and they only have three commentators listed for the Mets.
Gary Cohen does every game and he is joined by either Ron Darling or Keith Hernandez.
These days, Mike Krukow and Duane Kuiper do TV, and Dave Fleming and Jon Miller do the radio. They used to switch between TV and radio every three innings, but I don’t seem to remember hearing Jon or Flem on TV this year. Jon & Flem will trade play-by-play duties between each other, though. Flem actually called Bonds’ 756th home run, while Miller was doing color next to him. Greg Papa and FP Santangelo are sometimes milling around, especially when Miller is off doing ESPN games, but they are generally ignored by all.
She’s one of yours. She grew up in Boston as a Red Sox fan. Yet another reason why she shouldn’t be broadcasting for the Yanks.