It appears USC football head coach Lincoln Riley is losing a key part of his staff.

Trojans running back coach Kiel McDonald is finalizing a deal to take over that same position on Jim Harbaugh's Los Angeles Chargers staff, according to Adam Schefter. As the NFL insider pointed out, McDonald also had opportunities to be an OC in college but opted to coach at the pro level:

“Chargers are finalizing a deal to hire USC RB coach Kiel McDonald as their running back coach. McDonald had chances to become a college offensive coordinator but opted to become Jim Harbaugh’s RB coach. At Utah and USC, McDonald worked with backs such as Zack Moss and Marshawn Lloyd, a top prospect in this year’s draft.”

McDonald did a phenomenal job with USC football RB Marshawn Lloyd this past season, who will be taken high in April's NFL Draft. Before joining the Trojans, he was the running backs coach with Utah and helped develop Zack Moss into an elite talent. Moss has turned into a very respectable backup in the NFL with the Buffalo Bills and the Indianapolis Colts.

This is certainly a bit of a surprise and definitely hurts for USC. But, for the Chargers, it's a great pickup. McDonald knows what he's doing and certainly learned even more under Riley, who is a great offensive mastermind. McDonald will work with Austin Ekeler, the starter for Los Angeles who has all the potential to be one of the best backs in the entire NFL when healthy.