Jon Gruden, ESPN color analyst and former head coach of the Oakland Raiders, won’t be returning to the Silver and Black anytime soon. If owner Mark Davis is really going to spend on his next coach, as Adam Schefter of ESPN reported Sunday, he’s already running out of top-dollar candidates.

Gruden’s reluctance to leave the cushy broadcast booth leaves embattled San Francisco 49ers head coach Jim Harbaugh as the Raiders’ only endgame. That’s because spending big money on a mid-level candidate or even a hotshot college coach wouldn’t be money well spent in Oakland.

The Raiders are still two games away from the offseason, but it’s already setting up as if it’ll be Harbaugh or bust in 2015. The Raiders need a head coach like Harbaugh who can attract free agents and win immediately so they can get a new stadium.

If Mark Davis can’t turn his team into a winner soon, he’s going to be stuck somewhere he doesn’t want to be instead of in new digs in Oakland or Los Angeles. He’ll be stuck at O.co Coliseum in Oakland, seriously considering the Alamodome in San Antonio or sharing Levi’s Stadium in Santa Clara with the 49ers.

What’s more is that Harbaugh is the only available head coach who has the leverage to get some general manager-like powers. His power was at the center of the contract negotiation between Harbaugh and the 49ers.

If the Raiders are serious about making changes in the front office that include general manager Reggie McKenzie, it’s imperative they find an equal or better replacement. Despite his team’s lackluster record, McKenzie has built a base of young talent in Oakland and cleaned up the salary cap. Since the Raiders aren’t typically a desirable job for top football executives, it makes it hard to move on from McKenzie and his handpicked front office.

Harbaugh may do more than attract talent. He may be able to bring with him Philadelphia Eagles vice president of player personnel Tom Gamble. The two men worked together with the 49ers for over two years, and according to Tim Kawakami of the San Jose Mercury News, Gamble had a good relationship with Harbaugh.

Gamble also interviewed for general manager openings with the New York Jets and Jacksonville Jaguars two years ago but turned down a second interview with the Jaguars to try to land the job with the Jets that went to John Idzik. Becoming a general manager is clearly a step he wants to take, and he’s helped turn the Eagles around in just a couple years.

"I don't come in every day [and] fixate on (becoming a general manager),” Gamble said, via Jeff McLane of The Philadelphia Inquirer in 2013. “I don't think about it. To me, it's the inevitable if you have success and you're around success.”

Even more interesting is that Harbaugh and Gamble both have ties to the Raiders. Harbaugh’s first coaching job was with the Raiders, and he revered Al Davis. Kawakami confirmed that Gamble was the secret executive candidate the elder Davis tried to hire back in 2008. Per Kawakami, Gamble was also one of Al’s few confidantes in the last few years of his life.

Even if Gamble doesn’t come with Harbaugh, he’s still the ideal candidate for the Raiders because he doesn’t have many NFL ties. That opens the door for the Raiders to stick with their current front office with or without McKenzie at least on an interim basis to see how they work together.

Davis may welcome the idea of saving a little cash, especially because Harbaugh is going to come at a premium. The University of Michigan offered Harbaugh a six-year, $48 million contract, according to Ian Rapoport of NFL.com.

Jason La Canfora of CBS reported that Davis had double that out there for Gruden and that there was little doubt he could make the offer on Harbaugh, but Vic Tafur of the San Francisco Chronicle scoffed at that report.

Indeed, the numbers keep growing, and it’s becoming apparent that Harbaugh’s agent is doing a good job manipulating the process just as Gruden did to get more money and security from ESPN. The longer this process plays out, the more expensive Harbaugh could get.

Any team that wants Harbaugh will also have to give the 49ers something to secure his services. Anything more than a mid-round pick is probably too much, but that’s just another resource the Raiders will have to consider giving up to get the guy they want.

The personal side of it is working in the Raiders’ favor. Harbaugh’s wife and three young children live in the bay area, and he hasn’t worked outside of California since his playing career ended in 2001. There’s a certain appeal to the fact that Harbaugh wouldn’t have to move, he’d just have a little longer commute.

There are other good coaching candidates out there, and the Raiders might be better off not giving up a draft pick for Harbaugh, but none of them give the Raiders everything they need in one tidy package. It’s Harbaugh or bust now for the Raiders, no matter how they try to spin it if they don’t get him.