Until Joe Flacco came along in 2008, being the starting quarterback of the Baltimore Ravens featured all the job security of a department store Santa. Preceding him were the likes of Scott Mitchell, Jeff Blake and Steve McNair. And Elvis Grbac, Anthony Wright and Stoney Case.

There also was, for one season, a 34-year-old with an average arm and ferocious intensity whose mission on Sunday in New Orleans will be to stop his former team from winning Super Bowl XLVII. His name is Jim Harbaugh, and he coaches the San Francisco 49ers.

Harbaugh fashioned a solid career in 14 N.F.L. seasons, completing the second-most passes in Chicago Bears history before heading to Indianapolis, where the man known as Captain Comeback led the upstart Colts to within one play of the Super Bowl and was later chosen for the team’s Ring of Honor.

His next stop, in 1998, was Baltimore. He played 14 games. He lasted 13 months. He threw 12 touchdown passes and 11 interceptions. The Ravens lost 10 times. Harbaugh’s tenure in purple and black, brief and unproductive, was the opposite of his older brother John’s experience while steering the Ravens to three A.F.C. title games in five years.