In an 11-season career, Stennett was a.274 batter, with 41 home runs and 432 RBIs in 1,237 games. He was a good contact hitter with occasional power, and an aggressive and smart runner on the basepaths. As a fielder, Stennett had sure hands for fielding balls up the middle, as well as a strong and accurate arm to help complete double plays. Early in his career, Stennett played for four minor league teams in the Pirates' farm system: the Class AGastonia Pirates, the Class A Salem Rebels, the Triple-AColumbus Jets, and the Triple-A Charleston Charlies. He made his major league debut on July 10, 1971, leading off for the Pirates and going 0-for-4 against the Atlanta Braves. He collected his first major league hits a week later, going 2-for-4 against the San Diego Padres. On September 1, Pittsburgh faced the Phillies with the first major league all-black starting lineup. Stennett led off the game for the Pirates, who won 10–7. In his first three seasons with Pittsburgh, Stennett was used at shortstop and second base. He also played a solid defense at all three outfield positions, with an average arm and great reaction speed. He showed progress in, when he hit 10 home runs and 55 RBIs in 128 games. Following the 1973 season, Pittsburgh traded incumbent second baseman Dave Cash to Philadelphia and gave Stennett the starting job. Batting from the leadoff spot, he responded with a.291 average, 84 runs, 56 RBI, and a career-high 196 hits. On September 16,, Stennett became the only player in the 20th century to have seven hits in seven at bats in a nine-inning game, as Pittsburgh routed the Cubs, 22–0. Stennett's first hit in that game came off starter Rick Reuschel and his seventh was off Rick's brother Paul. Pittsburgh also set a major league record for the largest winning score in a shutout game in the modern era. He was the third player to collect seven hits in a single game, and the second to do it in a nine-inning game. With Stennett's position at second base secure in a lineup loaded with young hitters such as Dave Parker, Richie Zisk, and Rich Hebner and complemented by veterans Willie Stargell and Manny Sanguillén, Pittsburgh traded up-and-coming second baseman Willie Randolph to the New York Yankees after the 1975 season. On August 21,, Stennett was batting.336 for the season, but he broke his right leg while sliding into second base. He was out for the year and had fewer than the required number of at bats or plate appearances, falling short of qualifying for the batting title, won by teammate Dave Parker. In that season, Stennett collected a career-high 28 stolen bases. Stennett was part of the 1979 Pirates team that won the World Series. Stennett was a free agent at the end of the season and was signed by the San Francisco Giants to a five-year, $3 million contract in what would be one of the first "busts" of the free agent era. The Giants would release Stennett in April, with three years remaining on and $2 million left on his contract. Not yet 31 years of age, Stennett would never play in the majors again. He finished his professional career with 55 games for the Double-AWichita Aeros in 1983.
Later years
In August 2016, Stennett met with Brandon Crawford of the San Francisco Giants at Marlins Park, two days after Crawford's seven-hit game against the Miami Marlins. Crawford was the first major league player to collect seven hits in a game, although in extra innings, since Stennett.
