10 games, he was batting .526 with 4 home runs and 8 stolen bases. On May 1, 1987, he hit 2 home runs, including a grand slam. Two days later, he hit another three home runs—one each to left, center, and right field—including a grand slam, and a stolen base. He hit another grand slam that month, making him the first player in history to hit three in one month. During an eventful play in the late innings at Wrigley Field on September 4, Davis crashed into the outfield brick wall as he caught a deep fly ball; he laid on the ground several moments and was slowed afterward. Davis finished the 1987 season with a .293 average, 37 homers, and 50 steals. He became the first player in history to hit 30 homers and steal 50 bases in a season, despite playing in only 129 games. Prior to 1987, just six players had achieved the 30–30 club. That season, three others—including Strawberry, Joe Carter, and Howard Johnson—joined Davis in the 30–30 club. He led the league in power-speed number (42.53) with a mark that is the third-highest single season mark ever. From 1986 to 1990, Davis averaged 30 home runs and 40 stolen bases. During this time, he was one of the game's most exciting players and a very visible superstar player. He drew some MVP support every year from 1986 to 1990, finishing in the top 15 in the voting every year. From 1986 to 1989, he also finished in the NL's top 10 in home runs, slugging percentage, and OPS each year. While he had some other good seasons later in his career, injuries prevented him from reaching this type of peak again. In 1990, with a solid team around him, Davis was a key player in Cincinnati's "wire-to-wire" championship season. One of Davis' most famous moments was when he homered off Oakland's Dave Stewart in his first World Series at bat in 1990. The home run triggered a World Series sweep for the Reds. While diving for a ball during game 4 of the Series, Davis suffered a lacerated kidney, which required surgery. He also underwent off-season surgery on a knee that he had injured earlier in the season. After 1990, Davis was unable to get his career back on track. Injuries sabotaged his play in 1991, and he was traded to the Los Angeles Dodgers