Here's why you don't trade with your bitter rivals.

"Pedro Martinez does not wind up in Boston if Mike Stanley is not traded to the Red Sox for Tony Armas Jr. in that deal," Yankees GM Brian Cashman said on Tuesday.

Let the Yankees GM explain. In 1997, Yankees designated hitter Cecil Fielder breaks his thumb while trying to score in a game. The Yankees need a bat. They look to their rivals, Boston, who would finish with a 78-84 record. The two teams decide to swap Stanley, a catcher, and a minor leaguer for Armas Jr. and a player to be named later.

Fast forward to that offseason. The Red Sox make a deal with the Montreal expos, sending Carl Pavano and a player to be named later for Martinez. That player to be named later, of course, was Armas, and he helped the Red Sox land Martinez.

"Probably the best right-handed pitcher I've seen, Pedro Martinez," Cashman said.

Cashman and Epstein spoke briefly at "A Conversation with Brian Cashman and Theo Epstein" at Sacred Heart University about not being able to trade with each other as former executive rivals but now having that chance with Esptein now with the Cubs.

"We're looking forward to that," Epstein said before the event. "We had a few brief talks this winter but it will be nice to take each other seriously again."

Added Cashman: "Instead of fake talking, we can do something, maybe there will be a match at some point."

The Yankees and Red Sox have not had a trade since 1997, which not coincidentally was the last year before Cashman took over. Epstein even remembered a time when he tried offering Shea Hillenbrand for Nick Johnson and Cashman simply laughed at him.

"I think it's impossible only in the fact that unless one team's really good and one team is really bad," Cashman said before the event. "In that case we were trying to go for it and the Red Sox were rebuilding."