After a quick cup of coffee in 1963, Americo “Rico” Petrocelli debuted in 1965 and managed just a .232 average on a team that lost 100 games but also clocked 13 home runs and knocked in 33 runs while maintaining a slugging percentage better than the league average. He also showed solid play at short and, even with 18 errors and a .958 fielding percentage, the unusual combination of power and glove work normally uncommon among infielders made him a valuable commodity for the franchise.
Two years later, as the Red Sox surprised baseball by winning the American League pennant for the first time since 1946, Petrocelli batted a respectable .259 average while hitting 17 home runs, driving in 66, and making the first of two All-Star appearances. He also managed a fielding percentage of .970 in 141 appearances and assisted in 73 double plays.
Petrocelli continued to flex his impressive power at the plate; in 1969, he batted a career-high .297, amassed 40 home runs, best ever by a shortstop at that point, and drove in 97 runs while crossing the plate 92 times. He also improved defensively, too, committing just 14 errors, which tied another then-record at that position, and assisting in 103 double plays.
Over the next two seasons, he would collect another 57 home runs and 192 RBI and transition from short to third; when the Red Sox signed future Hall of Fame player Luis Aparicio prior to the 1971 season, Petrocelli became the full-time third baseman in Boston and responded by making just 11 errors and leading the league in fielding percentage at his new position.
Though he would continue to perform on the field after that, his numbers on offense would slowly decline over the last five years of his career as injuries began to cost him appearances; elbow problems surfaced in 1974 and he missed time not only at the start of the season but near the end as well. Calling it a career in 1976, Petrocelli finished with 210 home runs, 773 RBI, and a .251 batting average along with the recognition as one of the best power-hitting infielders in Red Sox history.