Rico Petrocelli spent 13 seasons with the Red Sox, mostly split between shortstop and third base. He might have played longer, but after two seasons of declining numbers, he was given his release late in Spring Training prior to the 1977 season. Petrocelli was a rare shortstop who could hit for a lot of power.
Signed as an amateur free agent in 1961, Petrocelli played a couple of seasons in the minors before making the Major Leagues for good in 1965. He played one game in Boston in 1963 and had a double and an RBI in four at-bats. His power showed up right away as he hit 19 home runs in AA ball in 1963. He had some trouble making contact, but was also a very good defensive shortstop.
Petrocelli's rookie season in 1965 saw him hit .232/.309/.412 with 13 home runs and 33 RBIs. Decent numbers, particularly his power numbers, for a shortstop at the time period. He hit more home runs (18), doubles (20), and drove in more runs (59) in 1966, but his on-base percentage and slugging percentage both declined.
It was the Impossible Dream season of 1967 that saw Petrocelli rise to stardom. He was an All Star for the first time in his career as he hit .259/.330/.420 with 17 home runs and 66 RBIs. His impressive year also led to him receiving some MVP votes. He hit just .200 in the World Series against the Cardinals, but did hit two home runs in Game 6 which Boston won 8-4 to stay alive and take the Series to seven games. His numbers in 1968 declined to .234/.292/.374 and 12 home runs.
If 1967 was his rise to stardom, 1969 saw him become an elite player for a few seasons. He had a monster year hitting .297/.403/.589 with a then-American League record 40 home runs for a shortstop. He also drove in 97 runs, hit 32 doubles, and walked 98 times. He was an All Star for the second time and finished seventh in the MVP vote. He might have been higher if Boston was in contention. He had another good season in 1970 with a slash line of .261/.334/.473 and slugged 29 home runs. He drove in a career-high 103 runs. 1971 was his last season as a shortstop and his last elite season. He hit 28 home runs and drove in 89 runs with a line of .251/.354/.461.
Boston acquired future Hall of Fame shortstop Luis Aparicio prior to the 1972 season and moved Petrocelli to third. As good a defensive shortstop as he was, he was even better at third and holds a lifetime .970 fielding percentage as a third-baseman, sixth highest of all-time. He continued to be a steady performer at the plate for the next three seasons, hitting around 15 home runs each year , but he was no longer the elite player he was 1969-1971.
The 1975 season saw the first major signs of decline as Petrocelli hit just .239/.310/.333 with just seven home runs. But he performed quite well in the postseason, hitting .308 with four RBIs. In his final season in 1976 he hit .213 with three home runs and lost his job at third to Butch Hobson. He was released prior to the 1977 season.
Petrocelli's single-season home run record for AL shortstops lasted for many years. He hit .251/.332/.420 for his career with 210 home runs and 773 RBIs. He spent his entire career with the Red Sox and later managed in the minor league system.