Neither ASU or Bradford, who has been projected as high as a second-round pick, have made an official announcement, but Liz Mullen of the Sports Business Journal is reporting that he has signed an agent at Athletes First, which would make him ineligible to return to school.
Yankey, a two-time All-American considered to be a first-rounder, announced his decision through a school press release.
"I reached my decision following conversations with family and coaches, and am greatly looking forward to the next chapter in life," Yankey said in the release. "The decision was not easy. I have loved my time at Stanford and am a proud member of Nerd Nation. I am humbled at the prospect of joining a long list of Stanford alumni currently playing in the NFL."
Yankey, a senior set to graduate this spring, had the option of coming back for a fifth year after receiving a medical redshirt as a freshman. Bradford departs after his junior year.