The 2013 schedule will not be released until later this month, but a few items have leaked out. After starting and ending the season mid-week the last two years, the season goes back to starting on Monday (April 1) and ending on Sunday (September 29). As expected, there will be one inter-league series going on at all times.
Of specific interest to Tigers fans, each AL Central team will play three games against each of the five teams in the NL East plus four games (two home and two away) against their "rival". So, the Tigers will play three games versus Atlanta, Miami, New York, Philadelphia, and Washington and probably four versus Pittsburgh (their rival this year).
it is not known how the intra-league schedule will work out. The rumor in the FanGraphs article above is that there may be more of a balanced schedule. That's not something I favor as there is no logic to having divisions and a balanced schedule. I'll wait until we hear something more solid before I complain too much though. Currently, they play 18 games versus teams within the division and 6 or 9 against the other two divisions. I could imagine them playing 14 games versus divisional rivals and nine versus most other teams.