Complex sentence: On May 11,2011, the Yankees announced that Monahan would retire following the 2011 season, and on June 26,2011, the team honored him at their annual Old-Timers' Day.
Split into simpler sentences: On May 11,2011, the Yankees announced that Monahan would retire following the 2011 season. On June 26,2011, the New York Yankees honored him at Old-Timers' Day.