Who can play in the play offs?

From:  "Sal"

Both the Yankees and the Red Sox are most likely going to be in the playoffs. Can the Red Sox and Yankees play in the first round of the playoffs, even though they are in the same division?

Nick helped out with this: 

Yes the Yankees and the Red Sox could have played each other in the first round of the playoffs. Its just however they set up the brackets to start the playoffs.

Todd responded with this: 

No! Being a die-hard Yankees fan, I know this answer easily. The keywords that you used are "same division" which means only one can ever play in the playoffs.

David K did research and reported back with this: 

As an avid baseball fan, I can answer this question. NO, the way Major League Baseball sets up its playoff structure, a team that is a "Wild Card" CANNOT play the division leader from its own division in the first round of the playoffs. A "Wild Card" team will always play the division leader with the best record OTHER than the leader of its own division.
As for the Red Sox in 2003, this rule just delayed the inevitable -- a loss to the Yankees.

Jonathan summed up with this: 

Yes both the Red sox and the Yankees can make the playoffs, due to the Wild card spot. Which is the best team record w/o winning that division.