Jim Harbaugh was born with a football in his right hand. Forty years later, after 15 seasons as an NFL quarterback, he did what his father did — and what his brother and brother-in-law do — he turned to coaching.

“My dad’s a coach,” said Harbaugh, now head coach at the University of San Diego, which will host the Bulldogs Saturday. “He’s been coaching for 43 years. I sort of grew up around coaching — games on Saturdays. So I knew I’d play as long as I could and then start coaching. It’s such a great profession. I was always so proud of him growing up. He coached at Michigan and he was a celebrity almost. Stems from him, my mom, the relationship they had, the relationships he had with other coaches. Personally, as an adult, it’s the way I’m wired. I need competition.”

Indeed, the coaching bug bit Harbaugh even before his playing career was over. Over his final eight seasons in the NFL (1994-2001) — including 1995, the year in which he finished runner-up in the MVP voting — Harbaugh was an NCAA-certified unpaid assistant coach under his father, Jack, at Western Kentucky University, serving as offensive consultant, scout and recruiter.

When he finally took the reins of his own team, at San Diego before the 2004 season, coaching did not seem to come as naturally for the son as it had for the father. The Toreros lost four of their first six games, including a 61-18 thrashing at the hands of Pennsylvania (lowly Princeton also edged USD a week later, 24-17).

“We did have a tough schedule,” Harbaugh said. “But the one thing about the west-coast offense is it takes some time to learn.”

It takes five games, it turned out. In San Diego’s final loss of the season, quarterback Todd Mortensen carved up the Drake defense for 347 yards passing.

He, Harbaugh and the Toreros never looked back. After the team reeled off five consecutive victories to close out the season, Mortensen was named Pacific Football League co-Offensive Player of the Year and was signed by the Detroit Lions and Harbaugh — the former Heisman finalist, first-round pick and Pro Bowler — was one of the hottest names in Division I-AA coaching.

“I take pride in the entire team,” Harbaugh said when asked if he favored quarterbacks over his other players. “Quarterback is an important position, probably the most important on offense because he handles the ball every play. Maybe I’m a little biased for having played it, and since I coach the quarterbacks, but it’s the head coach’s responsibility for the success of the whole team, and I take great pride in wins and losses.”

This season, with new starters at running back and quarterback, the Toreros (2-0) picked up right where they left off, vanquishing Azusa Pacific and Southern Oregon by a combined count of 81-6.

Still, Harbaugh is quick to point out that Yale might just be in another class than San Diego and the rest of the PFL, widely regarded as second-tier within I-AA.

“We definitely welcome the competition with a team with the tradition of Yale,” Harbaugh said. “Watching them on film, I think it’s a great football team and should be a great challenge for our team.”

It might please the Eli coaching staff to hear that Harbaugh was most concerned about Yale’s wideouts, a major source of consternation for the Bulldogs since a preseason injury to receiver Chandler Henley ’06 left the team without any starting experience at the position.

“They have playmakers on both sides of the ball,” Harbaugh said. “I’m really impressed with their receiving corps. They’re really athletic at that position.”

The upcoming battles in the trenches have also cost San Diego’s coach sleep this week.

“They have such great size and strength,” he said. “They’re really big in the lines. That’ll be a key matchup for us. It’s sort of a David and Goliath thing.”

Nevertheless, despite an 0-2 mark against Ivy League foes, Harbaugh is not worried about making a statement to the choice world of northeastern football.

“Do I feel extra pressure? I don’t feel any pressure. I don’t have to block anybody or tackle anybody.”