Well the Mariners/Athletics schedule for these opening series games is brutally strange:

March 28-29: Two game regular season opening series in Tokyo v. A's
March 31-April 4: Five Cactus league exhibitions in Arizona
April 4-5: Two game regular season "opener" in Oakland

Why? Seattle already travels more than any team in the league. That's more miles than St. Louis will travel in the first month of the season, for ONE series!

Has any regular season began, then a team reverts to spring training games only to begin the season again? Has this happened before?