1) Tony Lazzeri of the New York Yankees on May 24, 1936.
2) Frank Robinson of the Baltimore Orioles on June 26, 1970.
Only one pitcher has managed to hit two grand slams in one game. Tony Cloninger, then of the Atlanta Braves, managed this feat in a game against San Francisco in 1966.
Yes, in AUG 6th, 1986, the Rangers and the Orioles did it.
1
In 2011, the Yankees hit ten grand slams. They were hit by Robinson Cano (3), Mark Teixeira (2), Jorge Posada (1), Alex Rodriguez (1), Curtis Granderson (1), Russell Martin (1) and Francisco Cervelli (1).
Tony Cloninger hit two grandslams on July 3, 1966 against the San Francisco Giants.
Unfortunately, the most recent data I could find was for the 2008 MLB season. In 2008, 124 grand slams were hit (72 in the AL and 52 in the NL) in 2428 total games for an average of 1 grand slam every 19.58 games. The most grand slams hit in an MLB season is 176 (89 in the AL and 87 in the NL) in 2429 games in the 2000 season for an average of 1 grand slam every 13.80 games.
Yes, in AUG 6th, 1986, the Rangers and the Orioles did it.
1
In 2010, the Yankees grand slams were hit by Alex Rodriguez (3), Robinson Cano (2), Jorge Posada (2), Mark Teixeira (1), Curtis Granderson (1) and Brett Gardner (1).
In 2011, the Yankees hit ten grand slams. They were hit by Robinson Cano (3), Mark Teixeira (2), Jorge Posada (1), Alex Rodriguez (1), Curtis Granderson (1), Russell Martin (1) and Francisco Cervelli (1).
Robin Ventura hit 10 grand slams with the White Sox and 18 overall in his career. Ventura hit 2 slams for the Sox in the 1991, 1993, 1995, and 1996 seasons and 1 slam in the 1994 and 1998 seasons.
19 by Eddie Murray. Murray had 19 grand slams in 21 seasons (1977-1997). He hit 16 grand slams for the Baltimore Orioles, 1 for the Los Angeles Dodgers, and 2 for the New York Mets. He is 3rd in MLB career grand slams behind Manny Ramirez (20) and Lou Gehrig (23).
Tony Cloninger hit two grandslams on July 3, 1966 against the San Francisco Giants.
6 ... 2 in 1947 and 1 in 1936, 1941, 1946, and 1952.
7 ... 2 in 1933 and 1942 and 1 in 1935, 1938, and 1941.
In MLB between 1954-2010, there were 53 grand slam home runs hit by pitchers, 51 in the regular season and 2 in the post season. During this time frame, 6 pitchers hit 2 grand slams (Camilo Pascual, Tony Cloninger, Dave McNally, Rick Wise, Bob Gibson, Denny Neagle) and 41 have hit 1. Both of Cloninger's slams came in the same game ... one of McNally's two came in the World Series, the only pitcher to hit a grand slam in the World Series ... Neagle gave up a slam to a pitcher (Kevin Tapani).
In MLB, 1 ... on June 22, 1977 off of Joe Hoerner of the Cincinnati Reds.
Robin Yount hit three career grand slam home runs, 2 in the 1980 season and 1 in the 1984 season.