Over the last couple of years, Major League Baseball has released its complete schedule for the following year about mid-September. It's likely they'll do the same this year, but at least one portion of the 2014 schedule has leaked out, says Gordon Edes of ESPN Boston:
Ten years after the Red Sox won the World Series that ended their 86-year-long famine, the architect of that team, Theo Epstein, will have the perfect excuse to return. The Chicago Cubs, the team that Epstein now runs as president of baseball operations, are scheduled to visit Fenway Park for a three-game series June 30-July 2 in 2014, according to an industry source with access to the preliminary major league baseball schedule. The schedule is subject to the approval of all 30 teams, as well as the players’ union, so some changes almost certainly will be made, but they are expected to be minor.
While the rest of that article concerns the Red Sox schedule, it also contains clues as to the overall schedule. This year, for example, the Cubs' interleague schedule was against the American League West (and the White Sox). It included four games, two at each park, against the White Sox, and games against all the A.L. West teams as follows: one three-game series against four of the teams, and four games, two at each park, versus the fifth (in the Cubs' case, that was the Angels, resulting in a weird two-game road trip to Anaheim in June).
Edes' article indicates that this pattern will continue in 2014 (note, we as Cubs fans are used to thinking "White Sox" when we see "Sox" in an article, but obviously, he's referring to the Red Sox here):
The Sox will be playing NL Central opponents in interleague play, in addition to a home-and-home series against the Braves: two games in Atlanta May 26-27 followed by two games in Fenway May 28-29. The Reds come to Fenway Park for two games May 6 and 7. The Sox play the Cardinals in St. Louis Aug. 5-7, the Reds in Cincinnati Aug. 12-13, and the Pirates in Pittsburgh Sept. 16-18.
The Braves are the Red Sox' designated "interleague rival", as the White Sox are with the Cubs.
This scheduling pattern, presuming it holds, will have the Cubs facing American League East teams in interleague play in 2014. The Cubs last played A.L. East teams in 2008 (except for the 2011 visit of the Yankees and 2012 visit of the Red Sox to Wrigley Field); their most recent series against A.L. East clubs were:
Team At Wrigley On Road Red Sox 2012 2011 Yankees 2011 2005 Orioles 2008 2003 Blue Jays 2005 2008 Rays 2003 2008
If I had to guess -- and this is strictly speculation -- I'd guess we'll see the Rays and Blue Jays for three-game sets at Wrigley, and will travel to either New York or Baltimore for a three-game series, and the team that doesn't get the three-game visit from the Cubs between the Yankees and Orioles will be the one that has the four-game split, two at each park, as the Cubs and Angels did in 2013. That would make 20 interleague games, same as this year.
The full 2014 schedule should be released sometime in mid-September.