Complex sentence: Burkett was a National League All-Star in 1993 and 2001, and he retired following the 2003 season after going 12--9 with the Red Sox at age 38.
Split into simpler sentences: Burkett was a National League All-Star in 1993 and 2001. Burkett retired following the 2003 season after going 12--9 with the Red Sox at age 38.