James Harold Umbarger (born February 17, 1953) is an American former professional baseball pitcher. He attended Grant High School in Van Nuys, California, and was the 33rd pick in the 1971 Major League Baseball draft by the Cleveland Indians, but opted to attend Arizona State University. In 1974, The Sporting News named Umbarger as honorable mention on the All-America team. He was later selected in the 16th round of the 1974 Major League Baseball draft by the Texas Rangers.

Umbarger made his major league debut in April, of 1975, with the Rangers, and had a successful rookie season for the team, going 8-7 in 56 games (12 of them starts, with 2 shutouts), with a 4.12 ERA. The following season, Umbarger started 30 games for the Rangers, going 10-12 (with 3 shutouts) with a 3.15 ERA.

Prior to the 1977 season, Umbarger was traded to the Oakland Athletics, along with Rodney Scott, for outfielder Claudell Washington.^[1] Umbarger was sold back to the Rangers August 24, 1977. Umbarger finished the 1977 season with the Rangers and returned for the 1978 campaign, appearing in 32 games and posting a 4.88 ERA. The 1978 season would be Umbarger's last in the major leagues.

Umbarger continued to pitch in the minors through 1983. In 1981, he pitched 10 innings of scoreless relief in the longest professional baseball game ever played, a 33-inning marathon between Pawtucket and Rochester.