Complex sentence: Orlando City SC selected Arrieta in the 6th round of the 2014 MLS Expansion Draft; he was traded to D.C. United ahead of the 2015 season in exchange for an international roster spot.
Split into simpler sentences: Orlando City SC selected Arrieta in the 6th round of the 2014 MLS Expansion Draft. He was later traded to D.C. United ahead of the 2015 season in exchange for an international roster spot.