Complex sentence: A separate uncovered bleacher section was added in left field in 1958 when the New York Giants moved to the city in 1958, playing at Seals Stadium for two years while Candlestick Park was under construction.
Split into simpler sentences: A separate uncovered bleacher section was added in left field when the New York Giants moved to the city in 1958. The Giants played at Seals Stadium for two years while Candlestick Park was under construction.