The Miami Dolphins are making a heavy push for Harbaugh, who still could opt to stay at Stanford.
As NFL.com and NFL Network previously reported, the 49ers' front-office structure could be a considerable hindrance to the team landing Harbaugh, who clearly is the top candidate.
The 49ers interviewed Oakland Raiders offensive coordinator Hue Jackson on Wednesday, but New York Giants defensive coordinator Perry Fewell will "slow play" San Francisco, according to a source, because he is very sensitive to being used to accommodate the Rooney Rule, which requires team to interview minority candidates. It's clear to Fewell that Harbaugh is the 49ers' top choice.
NFL Network and Fox analyst Brian Billick remains a candidate for the 49ers job, assuming Harbaugh doesn't take it.
The 49ers, through the process of interviewing general managers, heard sterling recommendations for former Denver Broncos coach Josh McDaniels and consider him a strong candidate. However, a source close to McDaniels said its highly unlikely he would go to San Francisco because of issues with the personnel and front-office structure.
The 49ers likely will interview Philadelphia offensive coordinator Marty Mornhinweg once he becomes available (the Eagles are playing this week), and they are expected to hire an offensive-minded coach if at all possible.
Had the 49ers changed their structure and been willing to hire an outside GM, then meet the financial threshold that Harbaugh is commanding on the market, they could have built a dream staff, according to sources.
NFL Network insider Michael Lombardi interviewed for the GM position Tuesday in San Francisco. Lombardi has strong ties to Harbaugh, but also McDaniels, with the possibility of having McDaniels as offensive coordinator and another former head coach as defensive coordinator.