To give an example of established players who jumped straight from the Negro Leagues to MLB. Monte Irvin had a .990 OPS in 1946, .898 in 1947 and .782 in 1948 (Negro Leagues). With the NY Giants .889 in 1950, .929 in 1951, .801 in 1952 and .947 in 1953.

Larry Doby hit .333/.420/.550 (.970 OPS) in his last full season in the Negro Leagues in 1946. He hit .326/.442/.545 (.986 OPS) with Cleveland in 1950, after two very solid years as a well-above average hitter in 1948 and 1949.

There are many, many baseball historians who know WAY more about the Negro Leagues than I do. But something that has always stood out to me. Not only can you tell the caliber of the league by how players put up similar numbers in the majors than they did in the Negro Leagues.

But you can also tell by how few crazy stat outliers there are. If you put an MLB star in a minor league, they'd blow the league away. Look at Lefty Grove in the International League in the early 20s and he strikes out 330 in a year that the MLB leader struck out 197.

Put Bill Kennedy (a pretty mediocre major leaguer) in the Coastal Plain league in 1946 (one year before he heads to the majors) and he strikes out 456(!)

Even with a shorter season (which leads to more outlier stats), the talent in the Negro Leagues was solid enough and well distributed enough that you don't see Larry Doby or Monte Irvin hitting .400 every year.