Complex sentence: The Orioles spent most of the first three months of the season battling with the Toronto Blue Jays for first place in the division before the Jays took the lead for good on June 20.
Split into simpler sentences: The Orioles spent most of the first three months of the season battling with the Toronto Blue Jays for first place in the division. The lead switched back and forth between the two teams before the Jays took it for good on June 20.