 The Mansfields entered the professional National Association for , which begins Murnane's major league career in records that count the NA as a major league.He was the Mansfields' regular first basemen; that would be his most common fielding position but he played only a few full seasons "every day".Following the 1872 Mansfields, Murnane played in the majors for the Philadelphia Athletics (1873–74), Philadelphia White Stockings (1875), Boston Red Caps (1876–77), Providence Grays (1878)—as the first player signed by a new club—and finally the Boston Reds (1884), whom he also managed.