Answer by taking a quote from the following article:

Reginald Martinez Jackson (born May 18, 1946) is an American former professional baseball right fielder who played 21 seasons for the Kansas City / Oakland Athletics, Baltimore Orioles, New York Yankees, and California Angels of Major League Baseball (MLB). Jackson was inducted into the National Baseball Hall of Fame in 1993. Jackson was nicknamed "Mr. October" for his clutch hitting in the postseason with the Athletics and the Yankees. He helped Oakland win five consecutive American League West divisional pennants, three consecutive American League pennants and three consecutive World Series titles, from 1971 to 1975.

In the 1966 Major League Baseball draft on June 7, Jackson was selected by the Kansas City Athletics. He was the second overall pick, behind 17-year-old catcher Steve Chilcott, who was taken by the New York Mets. According to Jackson, Winkles told him that the Mets did not select him because he had a white girlfriend. Winkles later denied the story, stating that he did not know the reason why Jackson was not drafted by the Mets. It was later confirmed by Joe McDonald that the Mets drafted Chilcott because of need, the person running the Mets at the time was George Weiss, so the true motive may never be known.  Jackson, age 20, signed with the A's for $95,000 on June 13 and reported for his first training camp with the Lewis-Clark Broncs of the short season Single-A Northwest League in Lewiston, Idaho, managed by Grady Wilson. He made his professional debut as a center fielder in the season opener on June 24 at Bethel Park in Eugene, Oregon, but was hitless in five at-bats. In the next game, Jackson singled in the first inning and homered in the ninth. In the home opener at Bengal Field in Lewiston on June 30, he hit a double and a triple. In his final game as a Bronc on July 6, Jackson was hit in the head by a pitch in the first inning, but stayed in the game and drove in runs with two sacrifice flies. Complaining of a headache, he left the game in the ninth inning, was admitted to St. Joseph's Hospital in Lewiston, and remained overnight for observation.  Jackson played for two Class A teams in 1966, with the Broncs for just 12 games, and then 56 games with Modesto in the California League, where he hit 21 homers. He began 1967 with the Birmingham A's in the Double-A Southern League in Birmingham, Alabama, where Jackson got his first taste of racism, being one of only a few blacks on the team. He credits the team's manager at the time, John McNamara, for helping him through that difficult season.

Did he have any other issues with his race?
in Birmingham, Alabama, where Jackson got his first taste of racism, being one of only a few blacks on the team.