Because of the lack of statistical records kept in the Negro Leagues, it is hard to measure exactly how good Gibson's numbers really were. His Hall of Fame plague (enshrined in 1972 by the special committee on the Negro Leagues) says that he hit "almost 800 homeruns in 17 years". Research done by the special committee on the Negro Leagues states that they have proof of 270 career HRs. According to baseball reference, boxscores and stats were kept for 173 HRs. We obviously know why most of what Gibson did was not recorded. That is more of a shame than anything else other than this man not getting a chance to play in the major leagues.
Josh Gibson hit .366 for his career in the Negro Leagues, Mexican League and in Winter Ball in Cuba and the Dominican. There is no doubt in my mind that he would have been one of the greatest baseball players in MLB history had he been allowed to. He was better than his contemporaries, Mickey Cochrane and Bill Dickey. His power and ability to hit for average probably put him ahead of Yogi Berra, Johnny Bench, Carlton Fisk and Mike Piazza as far as catchers go. Some have said he hit as many as 84 HR in one season and hit the only ball completely out of Yankees Stadium.
Gibson should have been allowed to play in the major leagues. If it seems like I am repeating myself, and maybe I should, I probably am. One of the finer talents this game has ever seen was kept from playing the greatest baseball game ever just because of his skin color. Walter Johnson and Carl Hubbell were among players who stated any team could use a talent like that. His not being in the MLB gives critics reasons to smear what he had done. Some say the competition was not up to par as he played against some semi-pros and amateurs. Josh Gibson is the story of strength and determination. Yes, Jackie Robinson had it tough when he became the first African American to play major league baseball. But, when Jackie made his debut April 15, 1947, some of Josh Gibson had to be in him. Gibson had just passed away after playing professional baseball for nearly half of his life. He mastered what he had control of, playing the game he was allowed to play.
Based on the player he was, I believe it is a fair statement if he is put into the top five or ten best players to ever play this game.