Background: Leonard Guy Ford Jr. (February 18, 1926 - March 14, 1972) was an American football player from 1944 to 1958. He played college football for the University of Michigan and professional football for the Los Angeles Dons, Cleveland Browns and Green Bay Packers. He was inducted into the Pro Football Hall of Fame in 1976 and the University of Michigan Athletic Hall of Honor in 1996. Ford was an all-city athlete at his high school in Washington, D.C., and attended Morgan State University after graduating in 1944.
Context: By 1947, Ford had grown to 215 pounds, 25 pounds heavier than he had weighed in 1945. Led by All-American halfbacks Bob Chappuis and Bump Elliott, the undefeated 1947 Michigan team has been selected as the best team in the history of Michigan football. Nicknamed the "Mad Magicians", the Michigan squad finished with a 10-0 record, capped by a 49-0 victory in the Rose Bowl over USC on New Year's Day. Ford started only one game in 1947, as Bob Mann was the starting left end in eight of Michigan's 10 games. Even with reduced playing time, Ford caught a 35-yard touchdown pass in the first game of the season and had two receptions for 82 yards in the 55-0 win over Michigan State. He scored again in a game against Pitt. Ford's defensive performance was credited with shutting down Ohio State in the final game of the 1947 season. After the Wolverines' 21-0 victory over the Buckeyes, The Michigan Daily wrote:  "For the defense it was big Len Ford, who sparked a forward wall that never let the Bucks threaten. His end was practically impregnable. He smashed Ohio interference time and again, he continually harassed Dick Slager and Pandel Savic, the Ohio passers, and he made life miserable for Pete Perini, blocking one punt and rushing the Buckeye punter on nearly all of his kicks."  Michigan finished first in the AP Poll and won the 1947 college football national championship, sharing the honor with Notre Dame, which had been first in the polls before the Rose Bowl. After the 1947 season, the Associated Press (AP) selected Ford as a third-team All-American end and named teammate Bob Mann as a second-team All-American end. The AP also named Ford a second-team all-Big Nine Conference end. In the summer of 1948, he accepted an invitation to play for the college team in the College All-Star Game, a now-defunct annual matchup between the champion of the professional National Football League (NFL) and a selection of the country's best college players.
Question: Why did he only start in one game?

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