Jerry Blake Layne (born September 28, 1958) is an American umpire in Major League Baseball who has worked in the National League between 1989 and 1999, and throughout both major leagues since 2000. He wore uniform number 24 in the NL, but when MLB merged the AL and NL umpiring staffs in 2000, Layne was forced to switch to number 26, as AL umpire Al Clark, who also wore 24, had more seniority. When Clark was fired midway through the 2001 season by MLB, Layne reclaimed number 24 and has worn it ever since. With the retirements of Joe West and Gerry Davis, Layne became MLB's most senior active umpire for the 2022 season.