In 1935, Holder began his professional baseball career.
He played  with the Class-A Des Moines Demons of the Western League for the first part of the season, batting .304 with 105 hits, 14 doubles, 13 triples, and one home run in 88 games played with Des Moines.
Defensively, Holder, who played exclusively at second base for the Demons that year, compiled a .949 fielding percentage.
Holder managed to place third overall on the league's triples leaderboard, finishing just behind Charles Clements (15) Auggie Luther (14).

During the 1935 season, Holder joined the Triple-A San Francisco Seals of the Pacific Coast League (PCL).
The Seals brought him in to replace their regular second baseman, Art Garibaldi, who was sold to the St. Louis Cardinals.
Holder played the remainder of the season with San Francisco, batting .250 with 12 hits in 48 at-bats.
Holder's fielding percentage increased after joining the Seals, going from .946 to a combined .948 between the two clubs.
Overall as a member of the Seals, his fielding percentage was .958.
Holder spent his first full season with the San Francisco Seals in 1936.
In 152 games played, he compiled a .289 batting average with 27 doubles, 11 triples, and one home run.
In the field, Holder played at second base, putting up a .953 fielding percentage.

In 1937, Holder cracked the Seals' Opening Day batting order.
In May, he was converted to an outfielder after injuries to Seals players Ted Norbert and Johnny Gill.
Holder finished the season with a .319 average with 155 hits, 27 doubles, eight triples, and two home runs in 135 games played.
His fielding percentage that season was .968.
In July 1938, the Associated Press noted that it was possible that Holder would signing with a Major League Baseball (MLB) team that season, although nothing ever came of it.
On the season, Holder batted .330 with 193 hits, 26 doubles, eight triples, and two home runs in 172 games played.
Amongst PCL batters that year, he finished seventh in batting average.
On defense, he compiled a .980 fielding percentage.

Before the start of the 1939 season, Holder re-signed with the Seals.
That year, he batted .314 with 200 hits, 34 doubles, 24 triples, and five home runs in 173 games played.
He led all league batters that season in triples.
Holder's triples mark tied the all-time PCL record, which was set by Truck Eagan in 1903.
His fielding percentage that year was .969.
After the season, Holder was pegged by the Seals to be drafted or purchased by an MLB team, but was passed-up by scouts.
In February 1940, he re-signed with San Francisco.
On the year, Holder batted .274 with 143 hits, 19 doubles, seven triples, and one home run in 152 games played.
Defensively, he had a .962 fielding percentage.

During the 1941 season, Holder played 170 games with the Seals, batting .280 with 119 runs scored, 175 hits, 30 doubles, 10 triples, two home runs, 53 runs batted in (RBIs), and 11 stolen bases.
In the outfield, he compiled a .982 fielding percentage.
In 1942, Holder would continue his tenure in San Francisco, batting .298 with 113 runs scored, 194 hits, 36 doubles, nine triples, six home runs, and 51 RBIs in 179 games played.
Defensively, he put-up a .979 fielding percentage.

Before the start of the 1943 season, the San Francisco Seals were in talks with the Boston Braves, an MLB franchise, about selling Holder to them.
However, nothing ever came of it and instead the Seals traded Holder to the Hollywood Stars in exchange for Frenchy Uhalt, and Del Young.
In May 1943, Holder sustained a knee injury, which caused him to miss some playing time.
During his first season with the Stars, Holder batted .273 with 83 runs scored, 148 hits, 27 doubles, five triples, six home runs, 62 RBIs, and 11 stolen bases.
Defensively, he compiled a .975 fielding percentage.

In March 1944, Holder re-signed with the Stars.
On the season, he batted .280 with 119 runs scored, 163 hits, 28 doubles, eight triples, six home runs, 54 RBIs, and 21 stolen bases in 161 games played.
Holder placed second in league in runs scored, behind Cecil Garriott, who had
In 1935, Holder began his professional baseball career. He played  with the Class-A Des Moines Demons of the Western League for the first part of the season, batting .304 with 105 hits, 14 doubles, 13 triples, and one home run in 88 games played with Des Moines. Defensively, Holder, who played exclusively at second base for the Demons that year, compiled a .949 fielding percentage. Holder managed to place third overall on the league's triples leaderboard, finishing just behind Charles Clements (15) Auggie Luther (14).
During the 1935 season, Holder joined the Triple-A San Francisco Seals of the Pacific Coast League (PCL). The Seals brought him in to replace their regular second baseman, Art Garibaldi, who was sold to the St. Louis Cardinals. Holder played the remainder of the season with San Francisco, batting .250 with 12 hits in 48 at-bats. Holder's fielding percentage increased after joining the Seals, going from .946 to a combined .948 between the two clubs. Overall as a member of the Seals, his fielding percentage was .958. Holder spent his first full season with the San Francisco Seals in 1936. In 152 games played, he compiled a .289 batting average with 27 doubles, 11 triples, and one home run. In the field, Holder played at second base, putting up a .953 fielding percentage.
In 1937, Holder cracked the Seals' Opening Day batting order. In May, he was converted to an outfielder after injuries to Seals players Ted Norbert and Johnny Gill. Holder finished the season with a .319 average with 155 hits, 27 doubles, eight triples, and two home runs in 135 games played. His fielding percentage that season was .968. In July 1938, the Associated Press noted that it was possible that Holder would signing with a Major League Baseball (MLB) team that season, although nothing ever came of it. On the season, Holder batted .330 with 193 hits, 26 doubles, eight triples, and two home runs in 172 games played. Amongst PCL batters that year, he finished seventh in batting average. On defense, he compiled a .980 fielding percentage.
Before the start of the 1939 season, Holder re-signed with the Seals. That year, he batted .314 with 200 hits, 34 doubles, 24 triples, and five home runs in 173 games played. He led all league batters that season in triples. Holder's triples mark tied the all-time PCL record, which was set by Truck Eagan in 1903. His fielding percentage that year was .969. After the season, Holder was pegged by the Seals to be drafted or purchased by an MLB team, but was passed-up by scouts. In February 1940, he re-signed with San Francisco. On the year, Holder batted .274 with 143 hits, 19 doubles, seven triples, and one home run in 152 games played. Defensively, he had a .962 fielding percentage.
During the 1941 season, Holder played 170 games with the Seals, batting .280 with 119 runs scored, 175 hits, 30 doubles, 10 triples, two home runs, 53 runs batted in (RBIs), and 11 stolen bases. In the outfield, he compiled a .982 fielding percentage. In 1942, Holder would continue his tenure in San Francisco, batting .298 with 113 runs scored, 194 hits, 36 doubles, nine triples, six home runs, and 51 RBIs in 179 games played. Defensively, he put-up a .979 fielding percentage.
Before the start of the 1943 season, the San Francisco Seals were in talks with the Boston Braves, an MLB franchise, about selling Holder to them. However, nothing ever came of it and instead the Seals traded Holder to the Hollywood Stars in exchange for Frenchy Uhalt, and Del Young. In May 1943, Holder sustained a knee injury, which caused him to miss some playing time. During his first season with the Stars, Holder batted .273 with 83 runs scored, 148 hits, 27 doubles, five triples, six home runs, 62 RBIs, and 11 stolen bases. Defensively, he compiled a .975 fielding percentage.
In March 1944, Holder re-signed with the Stars. On the season, he batted .280 with 119 runs scored, 163 hits, 28 doubles, eight triples, six home runs, 54 RBIs, and 21 stolen bases in 161 games played. Holder placed second in league in runs scored, behind Cecil Garriott, who had
Brooks Holder