Frederick Charles Spenn
- Height 6' 2", Weight, 205 lb.
After attending the Al Somers umpire school in Florida, Spenn began umpiring in the Carolina League in 1970. He was promoted to the Southern League in the middle of 1971, then moved up to the American Association in 1973. During a Southern League game on June 15, 1972, he got into a heated argument with P Pablo Torrealba of the Savannah Braves, who he had just called out on strikes, which ended with the player chasing Spenn with his bat and striking him across the back, breaking the bat in the process. Torrealba was suspended for the remainder of the season, while Spenn was fined $50 for using abusive language.
A top-ranked umpire in the minors, he was first brought up by the American League as an injury replacement in 1977, when he worked 67 games. He was also up briefly in 1978, for another 28 games. When the members of the Major League Umpires Association went on strike at the start of the 1979 season, he was one of eight minor league umpires who accepted to work in the major leagues during the labor conflict. He was kept on staff after the strike was resolved, but was called a scab by the returning umpires and completely shunned by his peers. He lasted only two seasons as a full-time major league umpire, before being fired for under-performance after the 1980 season.