Complex sentence: Rico was deactivated from the military in December 1918, with the war in Europe having concluded, and planned on rejoining the Braves for the 1919 season, which would have been his third.
Split into simpler sentences: Rico was deactivated from the military in December 1918, with the war in Europe having concluded. He planned on rejoining the Braves for the 1919 season, which would have been his third.