professional baseball 1907–1910 After graduating from Chicago in 1907, Walker was hired as the athletic director and coach of four sports at Utah Agricultural College, now known as Utah State University. His 1907 Utah Aggies football team finished the season with a 6–1 record and outscored opponents 184 to 25. The 1908 team began the season 4–0 after scoring 138 points to 6 for the opponents. However, during the 1908 football season, one of Walker's football players was killed during a game, and the sport was abolished at the college. He spent the latter part of the 1908 season as an assistant coach under John P. Koehler at the University of Denver. In the summer of 1908, Walker played semi-professional baseball for the Rogers Parks team on the north side of Chicago. His pitching for Rogers Parks brought Walker to the attention of Chicago White Sox owner Charles Comiskey, who reportedly told Walker to "name his terms." In 1909, Walker returned to the University of Chicago as an assistant football coach under head coach Stagg. In 1910, he coached the University of Mississippi baseball team and led them to the southern college championship, finishing with a record of 11–3. At the conclusion of the college baseball season in 1910, Walker left Mississippi and joined the Cincinnati Reds as a pitcher. He appeared in one game for the Reds, pitching three innings on June 28, 1910, and allowing four hits and one earned run. Walker finished the 1910 season playing baseball for the San Francisco Seals in the Pacific Coast League. He appeared in 11 games for the Seals and compiled a record of 6–4 with a 2.68 earned run average. While playing for San Francisco in 1910, Walker identified himself as Frank Mitchell, leaving off his last name. Mystery surrounded his appearances in the Pacific Coast League. Some accounts indicate that he wore a mask while pitching for the Seals. After he won both games of a doubleheader over the Los Angeles Angels in early September 1910, allowing seven hits in the first game and six in the second, the Los Angeles Times first referred to him as "Mysterious Mitchell", reporting as follows:"The big feature of this first double-header was the work of the iron 'busher' who heaved in both games. In the first, of ten innings, he allowed but seven hits, and in the second, of seven innings, six