It was this performance that prompted sportswriter O. P. Caylor to give him his nickname of "Alamazoo". About his one game at the major league level, Jennings stated: We were all mixed with our signs...I signed for an outcurve, and got an inshoot which broke a couple of fingers. 'Go ahead' I said, 'I'll stay here all day even if I have to stop them with my elbows! You can't drive me away!'. The 10 passed balls set a record for catchers until Alex Gardner had 12 in a game on May 10, , also his only game at the major league level. On why Jennings, with little to no playing experience, was called upon to catch the hard-throwing Golden, Caylor stated: He looked so large and handsome, so very like a catcher...that Manager Chapman was mashed, and straightway engaged him, and clinched the bargain with a dinner. He endure his nickname for the remainder of his career, and sportswriters exaggerated his dismal performance more in the years afterward. He was also forced into retelling his experience many times in his life. In reading what Caylor had written, Jennings admitted: I read a few lines and wanted to fight. I read a few lines more and had to laugh. The first game Jennings worked occurred in minor league baseball, when, in 1878, he was unable to play due to a broken thumb. He began working as a major league umpire in 1882, when he worked two American Association games that were played locally in Cincinnati. Later, in 1884, he was assigned to work Northwestern League games in Ft. Wayne, Indiana to replace Charlie Cushman who had been injured by a stone thrown by an 11-year-old boy, who he had ejected from the stands earlier in the game. His work varied in 1884. In addition to minor league games, he was also picked to call an AA game on August 10, and in September, he was hired by the Union Association to work the remainder of their season. He was used in Baltimore, Washington D. C., and Cincinnati. For the 1885, he was hired by the Southern League, and he worked three AA games as well. He appeared in major league games infrequently over the next few years, calling 11 AA games in 1887, and one game each in 1889 and 1891. When not playing or umpiring, Jennings lived and worked in various places within his hometown of Cincinnati.