Complex sentence: He then spent 1940--44 in the top-level Pacific Coast League before his Major League debut, at age 28, with the 1945 Pirates during the final year of the World War II manpower shortage.
Split into simpler sentences: He then spent 1940--44 in the top-level Pacific Coast League. Salkeld made his Major League debut at age 28, with the 1945 Pirates during the final year of the World War II manpower shortage.