Barkley faced off against another Clarkson client in Ohio State's Terrelle Pryor in the Trojans' 18-15 win over the Buckeyes on Sept. 12.
The following weekend the quarterback guru was in attendance when two of his high school clients met in a nationally televised game in Sammamish, Wash., a Seattle suburb.
Oaks Christian (Calif.) senior Nick Montana squared off against Skyline (Wash.) senior Jake Heaps in Oak Christian's 28-25 victory. Montana is the son of NFL Hall of Famer Joe Montana.
"I was actually there for two games," Clarkson said last month while in the area working out Red Lion Christian Academy seventh-grader David Sills. "I had [Washington quarterback] Jake Locker. Jake Locker and Matt Barkley were both supposed to start in the USC-Washington game when I made the trip. But Barkley got hurt."
So he settled to witness Montana produce a come-from-behind victory reminiscent of his father's NFL exploits. In addition to Montana, Clarkson has worked with Trevor Gretzy, son of Wayne Gretzy, and Corde Broadus, son of Calvin Broadus, Jr. (a.k.a. Snoop Dogg).
His list of clients includes NFL players Ben Roethlisberger, Matt Cassel and Matt Leinart.
The former standout San Jose State quarterback is sought out because his endorsement and tutelage has become the gold standard for young signal callers.
If the 48-year-old likes what he sees and makes you his client, it's time to start pondering which college you want to play for. But getting picked is tough and expensive.
Clarkson is very selective. His list of clients is the football equivalent of getting into Massachusetts Institute of Technology (MIT). And be prepared to spend a lot of money.
The cheapest deal is around $625 a month. That includes 48 sessions a year but no one-on-one instruction.